Insects and Diseases A Popular Account of the Way in Which Insects may Spread or Cause some of our Common Diseases

CHAPTER X

Chapter 2011,818 wordsPublic domain

OTHER DISEASES, MOSTLY TROPICAL, KNOWN OR THOUGHT TO BE TRANSMITTED BY INSECTS

SLEEPING SICKNESS

One of the worst scourges of Africa and one that is to-day attracting world-wide attention is the disease known as trypanosomiasis, the terminal phase of which is sleeping sickness, one of the most ghastly diseases that we know.

Among the Protozoa referred to in one of the earlier chapters mention was made of certain trypanosomes which inhabit the blood of man and certain animals. Very little was known concerning these parasites previous to the beginning of the present century, but since that time several have been found to be of great economic importance. The group is being studied extensively and every day our knowledge of them is increasing so that we now know quite definitely the life-history of several.

_Trypanosoma lewisi_, a parasite of rats, is perhaps the best known as it is always common where-ever rats are found. Sometimes as many as 30% or 40% of the rats of certain districts are infected. It is thought that these are transmitted from rat to rat by the common rat-louse which serves as an intermediate host. Fleas may also act as disseminating agents.

A few other kinds cause serious disease of animals, but we are more interested just now in the particular one that is causing so much trouble in Africa. This parasite was discovered in 1902 and was named _Trypanosoma gambiensi_ (Fig. 111). Since then it has been found to be widely distributed. Although the natives have doubtless long been subject to the disease caused by this parasite, the recent influx of whites to these regions and the consequent movements of the natives have caused a great spread of the disease so that whole regions are now made desolate, the inhabitants dying or fleeing to escape the uncanny death.

The disease may run its course in a few months or it may take years. The symptoms are various, but infection is usually soon followed by fevers, sometimes mild, sometimes severe, which recur at irregular intervals. Certain glands or other parts of the body may become swollen. More or less extensive skin eruptions occur on all parts of the body and the patient gradually becomes anemic and physically and intellectually feeble. The nervous system seems to be affected by the parasite, either directly or by the action of the toxins it produces. The patient becomes more debilitated and morose with an increasing tendency to sleep, hence the name sleeping sickness. As the stupor deepens the patient looses all desire or power of exertion and as little food is taken he rapidly wastes away and finally succumbs for after this final stage is reached there is no relief.

It is definitely known that a species of tsetse-fly, _Glossina palpalis_ (Fig. 112), which somewhat resembles our stable-fly, is responsible for the dissemination of the disease, and some recent investigators have suggested that certain species of mosquitoes may also carry the parasite from one host to another. There still remains some doubt as to the exact manner in which the fly transmits the disease, but it seems altogether likely that it is an alternative host and does not serve as a simple mechanical carrier. In this respect it is like the mosquito which is one of the necessary hosts of the malaria parasites, and unlike the house-fly which carries the germs of various diseases in a purely mechanical way without serving as a definite necessary host for the parasite.

The tsetse-fly is found only in tropical Africa and is limited in its distribution there to certain very definite, narrow, brushy areas along the water's edge. If these places can be avoided there seems to be little danger. Those who are fighting the disease have found that if the brush in the vicinity of watering-places and ferry-landings is cleared away such places become comparatively safe. These flies do not lay eggs but produce full-grown larvæ which soon pupate in the ground.

ELEPHANTIASIS

In many tropical regions human blood as well as that of other animals is the normal habitat of certain worm-like parasites (Nematodes). They are not entirely confined to the tropics but may extend far up into the subtropical regions. Five or six different species of these parasites are known, only one of which, however, has been shown to be of any pathological importance, as far as human beings are concerned.

This species, _Filaria bancrofti_, is not only very widely distributed, but in regions such as some of the South Sea Islands a very large per cent of the natives have the filariæ present in their blood. When these parasites are withdrawn from the circulation and placed on a slide for study they are seen to be minute transparent, colorless, snake-like organisms inclosed in a very delicate sack or sheath. They are but a little more than one-hundredth of an inch long and about as big around as a red blood-corpuscle. These are the larval forms of the parasite and have been called by Le Dantec the micro-filaria.

If blood of the patient drawn from the skin, is examined during the day few if any of these parasites are found, but if it is examined between five or six o'clock in the evening and eight or nine o'clock the next morning they may be found in numbers. During the daytime they have retired from the peripheral circulation to the larger arteries and to the lungs, where they may be found in great numbers.

This night-swarming to the peripheral circulation has been found to be a remarkable adaptation in the life-history of the parasite, for it has been demonstrated that in order to go on with its development these larval forms must be taken into the alimentary canal of the mosquito. Most of the mosquitoes in which the development takes place are night-feeders, so that the parasites are sucked up with the blood of the victim. Once inside the stomach they soon free themselves from the inclosing sheath and make their way through the walls of the stomach and enter the muscular tissue, particularly the thoracic muscles. Here they undergo a metamorphosis and increase enormously in size, some attaining one-sixteenth of an inch in length.

After sixteen to twenty days they leave these muscles and make their way to other parts of the body. A few may be found in different parts of the abdomen, but most of them make their way forward into the head of the mosquito and coil themselves up close to the base of the proboscis, finally finding their way down into the proboscis inside the labium. Here they lie until an opportunity offers for them to escape to the warm blood of a vertebrate. They probably pass through the thin membrane connecting the labella with the proboscis and there find their way into the wound made by the puncture when the insect bites. Whether these parasites can gain an entrance into the circulatory system in any other way is not known. It has been suggested that the mosquitoes dying and disintegrating on the surface of water may liberate the filariæ which may later find their way into the system of the vertebrate host when the water is used for drinking, but most of the investigations made so far seem to indicate that they make their way directly from the proboscis into the new host.

Soon after entering the circulatory system of the human host the parasites make their way into the lymphatics where they attain sexual maturity, and in due time new generations of the larval filariæ or microfilariæ are poured into the lymph, and finally into the definite blood-vessels, ready to be sucked up by the next mosquito that feeds on the patient.

In most cases of infection the presence of these filariæ in the blood seems to cause no inconvenience to the host. They are probably never injurious in the larval stage, that is, in the stage in which they are found in the peripheral circulation.

In many cases, however, the presence of the sexual forms in the lymphatics may cause serious complications. The most common of these is that hideous and loathsome disease known as elephantiasis in which certain parts of the patient becomes greatly swollen and distorted. An arm or a leg may become swollen to several times its natural size, or other parts of the body may be seriously affected.

In some of the South Sea Islands 30% to 40% of the natives are afflicted in this way, some only slightly others seriously. There is little or no pain, but in severe cases the distorted parts often render the patient entirely helpless.

The exact way in which the parasites cause such swelling is not very definitely known. Manson, who has done more work on these diseases than any one else, believes that the trouble arises from the clogging of the lymphatic glands or trunks, thus cutting them off from the general circulation, in which case the affected parts may become distorted. This clogging of the passages is believed to be due to the presence of great numbers of immature eggs which have been liberated by parasites injured in some way before their eggs were entirely developed.

This interference with the lymphatic circulation brings about the anomalous condition of a patient with a serious filarial disease with fewer of the filarial parasites in his blood than one who is not so seriously affected. This is supposed to be due to the fact that the disease-producing parasites have died and that the lymphatics have become so obstructed that any microfilariæ they may contain cannot make their way into the general circulation. Such a patient then would not be as likely to infect a mosquito as would one less seriously affected.

It has always been thought that little or nothing could be done in the way of successfully treating this disease, but quite recently a French physician, who has been conducting a long series of experiments in the Society Islands, announced that he is able to cure many cases by certain surgical operations on the affected parts.

DENGUE OR "BREAKBONE FEVER"

This is another disease of the tropics often occurring in widespread epidemics. It is probably most frequently met with in the West Indies, but may occur in any of the tropical countries or islands. Occasionally it spreads into subtropical or even temperate regions. Several extensive epidemics have occurred in the United States. Once introduced into a community it spreads very rapidly and nothing seems to confer immunity.

The various names by which it has been called well describe its effect on the patient; breakbone fever, dandy-fever, stiff-necked or giraffe-fever, boquet (or "bucket") fever, _scarlatina rheumatica_, polka-fever, etc. While the suffering is intense as long as the disease lasts it seldom terminates fatally.

It has always been classed as a very contagious disease and it has not yet been definitely shown that it is not. Recent observations, however, have shown that it is probably caused by a certain Protozoan parasite that is found in the blood of dengue patients and several experiments have been conducted by Dr. Graham which seem to indicate that it is transmitted by mosquitoes. In these experiments, _Culex fatigans_, a common tropical or subtropical mosquito, was used. The same parasite that is found in the human blood may be found in the stomach and blood of the mosquitoes up to the fifth day after it has fed on a dengue patient.

Sick and healthy individuals were allowed to remain in close contact in a room from which the mosquitoes had been excluded, and the disease was not spread. Mosquitoes that had bitten dengue patients were taken to a higher region where dengue had never occurred and allowed to bite two healthy persons. Both developed the disease and as they were protected from other mosquitoes until they had recovered, the disease did not spread to others of the community. These and other observations seem to make a complete chain of evidence, and most medical men to-day accept the theory as well proved and in their practice take every precaution to prevent the spread of the disease by keeping the infected patient from being bitten by the mosquitoes.

The yellow fever mosquito is also suspected of carrying this same disease, and it is possible that other species are also concerned. If it is true that the parasite can be carried by several different species of mosquitoes this would account very largely for its rapid spread wherever it is introduced into a community. Where it occurs outside the tropics it is only in the warm summer months when mosquitoes are always abundant.

MALTA OR MEDITERRANEAN FEVER

This is also a tropical and subtropical disease that occasionally gets up into the temperate region, sometimes occurring in the United States. The fever begins with a severe headache, and other symptoms follow. It is usually of the remittent type and may continue for some months.

It is caused by minute bacteria (_Micrococcus melitensis_) and is a very infectious but not usually contagious disease. The germ is readily conveyed by inoculation, and several investigators have sought to show that the mosquito often serves as the inoculating agent. The disease is especially prevalent during the mosquito season, and has twice been conveyed to monkeys by infected insects.

LEPROSY

This loathsome disease has long been known to be caused by a particular bacillus (_Bacillus lepræ_), but the way in which this organism gains an entrance into the system is still unknown. Many theories have been propounded, but none of them has been well established. Within recent years the possibility of insects carrying the germ and in one way or another transmitting it to healthy individuals has been suggested and much discussed. As the lepræ bacilli are present in the skin and ulcers of leprous patients, insects sucking the blood or feeding on the sores could not help taking some of them into their body or becoming contaminated. These bacilli have been found at various times in the stomach or intestine of mosquitoes, fleas and bedbugs. So it is believed by some that these and other insects, such as lice and flies, may sometimes transmit the disease. On a previous page we have referred to the possibility of the face-mites acting as disseminators of leprosy.

Leprosy occurs most commonly among people where little attention is paid to bodily cleanliness. Such people are usually freely infested with various parasites that thrive well in the filth, so if the germs can be transmitted in this way the carriers are there in abundance.

The fact that the sores usually occur on exposed parts of the body has been pointed to as evidence that inoculation is due to such insects as flies and mosquitoes. It has been noted that leprosy is frequently very common in regions where elephantiasis occurs, suggesting the possibility of the same carrier, the mosquito, for both diseases. So while there is as yet very little evidence one way or the other, insects that are found around leprous patients are to be regarded with suspicion, for until we know more definitely just how the disease is communicated the insects must be looked on as possible sources of contamination.

KALA-AZAR OR DUM-DUM FEVER

This is a very fatal infectious disease of many tropical and subtropical regions, spreading terror among the natives wherever it occurs. It is caused by the presence in the system of Protozoan parasites, the so-called Leishman-Donovan bodies, that have recently been studied by several observers.

Dr. W.S. Patton of the Indian Medical Service has been making some extensive experiments with the common bedbug of India (_Cimex rotundatus_) which seem to demonstrate fully that this insect is responsible for the transmission of the parasite that causes the disease. He has found the parasite in all stages of development in the bedbug. This, taken with a number of other observations in regard to the tendency of the disease to cling to particular houses, makes a strong case against the bedbug. Manson, however, believes that the parasite may be transmitted by other agents also, possibly by means of flies that visit the sores or in other ways.

ORIENTAL SORE

This disease, once supposed to be confined to the Orient, is now found to be rather widely distributed throughout the tropics, where it is sometimes very prevalent. It is caused by the presence in the system of a parasite very similar to or identical with the one causing _kala-azar_ and is regarded by some as a modified form of that disease. The patient is affected with one or more serious sores or ulcers which usually occur on exposed parts of the body.

The parasite that causes the disease is supposed to be carried by insects either directly or indirectly.

In the latter case the insect may act as an intermediate host.

Dogs and camels are also attacked by this disease and may be sources of infection.

BIBLIOGRAPHY

A complete list of books and articles dealing more or less directly with the subjects discussed in this book would be too extended for use here. For the past ten or twelve years many of the medical and biological journals have contained articles in almost every issue, discussing these subjects in some of their phases. I have selected only a few of the more important of them, and these only the English ones, confining myself mostly to those that I have personally consulted, and giving brief annotations. Many of these will be found to include very full bibliographies of the particular subject treated.

In order to avoid repetition, references are given under one head only although many might properly be included in other sections as well.

PARASITES AND PARASITISM

BRAUN, MAX. Animal Parasites of Man. Translated by Pauline Falcke and edited by L.W. Sambon and F.V. Theobald. Third edition, 1906. A chapter on the general subject of parasitism and a description of parasites of all classes. Bibliography.

LEUCKART, R. The Parasites of Man and the Diseases Induced by Them. Eng. transl., London, 1886.

NEUMAN, THEO. Entoparasites and Hygiene. _Trans. Vassar Bros. Institute_, VII, 1895. A general discussion of parasitism; life-history of some common parasites that infest man.

NEUMANN, L.G. Treatise on the Parasites and Parasitic Diseases of the Domesticated Animals. Eng. transl. by Fleming, 1892.

RANSOM, B.H. How Parasites Are Transmitted. _Year Book U.S. Dept. Agric._, 1905, pp. 139-166 (pub. 1906). Discusses the ways in which parasites of all classes are transmitted.

SAMBON, L. The Part Played by Metazoan Parasites in Tropical Pathology. _Jour. Trop. Med. & Hyg._, Vol. XI, Jan. 15, 1908. A comprehensive discussion of this subject.

SHIPLEY, A.E., AND FEARNSIDES, E.G. Effects of Metazoan Parasites on Their Hosts. _Jour. Econom. Biology_, Vol. I, 1906, pp. 41-62. Discusses injury due to mere presence of parasite in host; to the migration of the parasite; loss to host by feeding of parasites; injury by certain toxins.

STILES, C.W. Diseases Caused by Animal Parasites. _Osler's Mod. Med._, Vol. I, 1907, p. 525. General discussion; Trematodes; Cestodes; Roundworms; Acariasis; Parasitic Insects; Myiasis.

VAN BENEDEN, P.J. Animal Parasites and Messmates. 1889. Contains much that is interesting.

WARD, HENRY B. Influence of Parasitism on the Host. _Proc. Amer. Assn. for Advancement of Science_, Vol. 56, 1907. A comprehensive statement of this subject. List of literature.

PROTOZOA

CALKINS, G.N. The Protozoa. _Osler's Mod. Med._, Vol. I, 1907, p. 353. General notes on the Protozoa; classification; reproduction; life-cycle of various forms. Regards Protozoa as subkingdom and the four great divisions as phyla.

CALKINS, G.N. Protozoölogy. N.Y., 1909. Chapters on parasitism, pathogenic Protozoa, etc.

CLARKE, J.J. Protozoa and Disease. London, 1903, Pt. I. Discusses the various protozoa that cause disease, and refers frequently to those that are transferred from host to host by insects.

CLARKE, J.J. Protozoa and Disease. London, 1908. Part II, comprising sections on the causation of smallpox, syphilis and cancer. Notes on parasitic Protozoa, tropical diseases, ticks, piroplasmosis, etc.

DANIELS, C.W. Persistence of the Tropical Diseases of Man Due to Protozoa. _Jour. Trop. Med. & Hyg._, 12, Aug. 2, 1909, pp. 232-234. Same in _Lancet_, II, 1909, p. 460. Good summary of present knowledge of the subject.

MINCHIN, E.A. Protozoa. In Albutt and Rolleston's _System of Medicine_, II, 1907, pp. 9-122. A comprehensive chapter on Protozoa. Many parasitic forms are figured and described. Bibliography.

MINCHIN, E.A. The Sporozoa. In Lankester's _Treatise on Zoöl._, Pt. I, pp. 150-360, 1903. Best account of this group, list of Sporozoan hosts. Bibliography.

BACTERIA

FLEXNER, SIMON. Relation of Bacteria and Sporozoa to Disease. _Science_, N.S., Vol. 27, No. 682, pp. 133-136. On these pages discusses relation of bacteria and Protozoa to human diseases.

JORDAN, EDWIN O. General Bacteriology. Philad., 1898. A good general treatment of the subject.

LEVY, ERNST, AND KLEMPERER, FELIX. Elements of Clinical Bacteriology for Physicians and Students (transl. by A.A. Eschner), Philad., 1909. Morphology and biology of bacteria; infection; immunity; specific diseases of bacterial origin, etc.

MUIR, ROBT., AND RITCHIE, JAS. Manual of Bacteriology. N.Y., 1903. Contains chapter on the relation of bacteria to diseases and discussion of several bacterial diseases.

STERNBERG, G.M. A Manual of Bacteriology. N.Y., 1893. Part III is devoted to pathogenic bacteria.

INSECTS AND DISEASE

HERMS, W.B. Medical Entomology, Its Scope and Methods. _Jour. of Eco. Ento._, Vol. 2, No. 4, 1909, pp. 265-268.

HOWARD, L.O. Insects as Carriers and Spreaders of Disease. _Year Book U.S. Dept. Agric._, 1901, pp. 177-192. Good review of the subject.

HOWARD, L.O. How Insects Affect Health in Rural Districts. _U.S. Dept. Agric., Farmers' Bulletin, No. 155_, 1902. Discussion of city and county conditions; protection from typhoid, malaria and yellow fever.

HOWARD, L.O. Economic Loss to the People of U.S. Through Insects That Cause Disease. _Bull. 78, U.S. Dept. Agric. Bur. of Ent._, 1909. A comprehensive discussion and summary of the subject. Discusses mosquitoes, flies, the Panama Canal, epidemic diseases and the progress of nations.

KELLOGG, V.L. Insects and Disease, Chap. XVIII, in _American Insects_, pp. 615-654, 1905. Discusses Mosquitoes and malaria; yellow fever and filariasis.

KING, H.H. Report on Economic Entomology of Khartoum, in _Third Rept. of Wellcome Research Lab._, 1908. Discusses insects injurious to man: mosquitoes, blood-sucking insects other than mosquitoes, etc.

MASON, C.F. The Spread of Diseases by Insects, with Suggestions Regarding Prophylaxis. _International Clinics_, Vol. II, 1904, pp. 1-21. A brief summary of the subject.

MCCRAE, JOHN. Recent Progress in Tropical Medicine. _International Clinics_, Vol. II, 1904, pp. 22-36. Discusses several diseases, some of which are transmitted by insects.

NUTTALL, G.H.F. On the Rôle of the Insects Arachnids and Myriapods as Carriers in the Spread of Bacterial and Parasitic Diseases of Man and Animals. A critical and historical study. _Johns Hopkins Hospital Reports_, Vol. 8, 1899, pp. 1-154. A review of all the literature up to this date. Important article.

NUTTALL, G.H.F. Insects as Carriers of Disease. Recent advances in our knowledge of the part played by blood-sucking arthropods (exclusive of mosquitoes and ticks) in the transmission of infectious diseases. Bericht über den XIV. Intern. Kongress für Hygiene und Dermogrophic. Berlin, 1907, pp. 195-206. Discusses protozoan and bacterial diseases.

STILES, C.W. Insects as Disseminators of Disease. _Virginia Medical Semi-monthly_, Vol. 6, No. 3, May 10, 1901, pp. 53-58. Good statement of subject with list of recent workers.

WHERRY, W.B. Insects and Infection. _Cal. State Jour. of Med._, Nov., 1907. Discusses the rôle of insects, ticks, etc., in the transmission of infectious diseases.

Symposium on Yellow Fever and Other Insect-borne Diseases. _Science_, N.S., Vol. 23, Nos. 584-585, 1906. The Protozoan Life-cycle, G.N. Calkins. Filariasis and Trypanosome Diseases, H.B. Ward. The Practical Results of Reed's Findings on Yellow Fever Transmission, J.H. White. Difficulties of Recognition and Prevention of Yellow Fever, Q. Kohnke. The Practical Side of Mosquito Extermination, H.C. Weeks. Without Mosquitoes There Can Be No Yellow Fever, Jas. Carroll. Estivo-autumnal Fever, Cause, Diagnosis, Treatment and Destruction of Mosquitoes Which Spread the Disease, H.A. Veazie.

MOSQUITOES--SYSTEMATIC AND GENERAL

BALFOUR, ANDREW, AND STAFF. _Second Report of the Wellcome Research Laboratories at the Gordon Memorial College_, Khartoum, 1906. Includes reports on work on mosquitoes and other noxious insects.

BOYCE, SIR ROBERT W. Mosquitoes or Man? The Conquest of the Tropical World. N.Y., 1909. Reviews medical and sanitary work in the tropics and discusses the relation of insects to various tropical diseases.

BUSCH, AUGUST. Report on a Trip for the Purpose of Studying the Mosquito Fauna of Panama. _Smith. Miscell. Coll._, Vol. 5, Pt. I, 1908, p. 49. Work that is being done in Panama to control the mosquitoes. Annotated list of species.

FELT, E.P. Mosquitoes or Culicidæ of New York State. In _N.Y. State Museum Bull. 79_, Entomology 22, 1904. Discusses distribution, migration and life-history of various species of mosquitoes and mosquito diseases. Bibliography.

GILES, GEO. M. A Handbook of Gnats or Mosquitoes, Giving the Anatomy and Life-History of the Culicidæ. London, 1902. Whole subject treated very fully.

GRUBBS, S.B. Vessels as Carriers of Mosquitoes. _Pub. Health and Mar. Hospt. Ser. Bull._ II, Mar. 3, 1903. Believes that mosquitoes may come aboard when the vessel is lying at anchor one-half mile from shore, and that under favorable conditions they may come aboard when the vessel is fifteen miles from shore.

HOWARD, L.O. Mosquitoes. _Osler's Mod. Med._, Vol. I, p. 370, 1907. General notes on classification and habits particularly in relation to diseases.

HOWARD, L.O. Notes on Mosquitoes of the United States. _U.S. Dept. Agric., 1900. Div. of Ento. Bull. No. 25_, N.S. Account of the structure; biology; remarks on remedies.

HOWARD, L.O. Concerning the Geographic Distribution of the Yellow Fever Mosquito. _Public Health Rept., Pub. Health and Mar. Hospt. Ser._, Nov. 13, 1903. The same revised to Sept. 10, 1905.

HOWARD, L.O. Mosquitoes: How They Live; How They Carry Disease; How They Are Classified; How They May Be Destroyed. N.Y., 1901. One of the best popular books on mosquitoes.

MCCRACKEN, I. _Anopheles_ in California, with a Description of a New Species. _Entomological News_, Vol. 15, Jan., 1904. Records of three species, their breeding-places, habits, etc.

MITCHELL, EVELYN G. Mosquito Life. N.Y., 1907. A good popular account of the mosquitoes and their relation to disease. The appendix treats of mosquitoes and their possible relation to leprosy.

SMITH, J.B. Mosquitoes Occurring Within the State of New Jersey. Report of the New Jersey State Agric. Exper. Station upon the mosquitoes occurring within the State. Trenton, N.J., 1904. Habits, development, relation to disease, checks and remedies; systematic.

SMITH, J.B. The General Economic Importance of Mosquitoes. _Popular Science Monthly_, 70, 1907, pp. 325-329. Mosquitoes affect not only the health and comfort of the people, but hinder development of agriculture and thus affect land values.

SMITH, J.B. The New Jersey Salt-marsh and Its Improvement. _New Jersey Agricultural Experiment Station Bulletin_, 207, 1907. Shows that the increased value of the land drained in the antimosquito crusade more than pays for the cost of the drainage.

THEOBALD, F.V. Monograph of _Culicidæ_ of the World. Four Vols. and one Vol. of plates. London, 1901 to 1907. Vol. I contains 96 pages on structure, life-history, habits, etc. Vol. II contains a bibliography. Vol. Ill contains a list of species that carry disease.

THEOBALD, F.V. Mosquitoes or _Culicidæ_. In Albutt and Rolleston's _System of Medicine_, II, 1907, pp. 122-168. Structure, life-history, habits, distribution and classification of mosquitoes. Bibliography.

MOSQUITO ANATOMY

BERKELEY, WM. M. Laboratory Work with Mosquitoes. N.Y., 1902. Chapters on development, anatomy, dissection, malarial parasites, filarial disease, yellow fever.

DIMMOCK, GEO. Anatomy of the Mouth-parts and Suctorial Apparatus of _Culex_. _Psyche_, 3, pp. 231-241, Sept., 1881. Good.

IMMS, A.D. On the Larval and Pupal Stages of _Anopheles maculipennis_. _Journal Hygiene_, Vol. 7, No. 2, April, 1907. Morphology.

IMMS, A.D. On the Larval and Pupal Stages of _Anopheles maculipennis_. _Parasitology_, Vol. I, No. 2, June, 1908. Continuation of article in _Jour. Hyg._, Vol. 7, No. 2. Continues discussion of morphology.

NUTTALL, GEO. F., CORBETT, LOUIS, AND STRANGEWAYS-PIG, T. Studies in Relation to Malaria. Pt. I, The Geographical Distribution of _Anopheles_ in Relation to the Former Distribution of Ague in England. _Jour. Hyg._, Vol. I, No. 1, Jan., 1901.

NUTTALL, GEO. F., AND SHIPLEY, ARTHUR E. Studies in Relation to Malaria. Pt. II, Structure and Biology of _Anopheles_, _Jour Hyg._, Vol. I, No. 1, Jan., 1901: The Egg and Larva; Bibliography. Pt. II, cont, Vol. I, No. 2, April, 1901: The Pupa. Pt. II, cont., Vol. I, No. 4, Oct., 1901: Adult External Anatomy. Pt. II, cont., Vol. 2, No. 1, Jan., 1902: Ætiology of Adult. Pt. II, cont., Vol. Ill, No. 2, April, 1903: Anatomy of Adult.

THOMPSON, MILLETT T. Alimentary Canal of the Mosquito. _Proc. Bost. Soc. Nat. Hist._, Vol. 32, No. 6, 1905, pp. 145-202. Good summary of recent investigations.

WESCHE, W. The Mouth-parts of _Nemocera_ and Their Relation to the Other Families of _Diptera_. _Royal Microscopic Soc. Jour._, 1904, pp. 28-47. Discussion with illustrations of the mouth-parts of various _Diptera_.

MOSQUITOES--LIFE-HISTORY AND HABITS

AYERS, E.A. The Secrets of the Mosquito. A guide to the extermination of the prolific pest. _World's Work_, 1907, Vol. 14, pp. 8902-8910. Notes on life-history and methods of control.

JORDAN, E.O., AND HEFFERAN, MARY. Observations on the Bionomics of _Anopheles_. _Jour. Infec. Diseases_, II, 1905, pp. 56-69. Occurrence, breeding-places, habits, etc.

MORGAN, H.A., AND DUPREE, J.W. Development and Hibernation of Mosquitoes. _Bull. 40_, N.S., _Div. of Ento._, pp. 88-92, 1903. Results of observation on five genera of mosquitoes in the vicinity of Baton Rouge, La.

ROSS, E.H. The Influence of Certain Biological Factors on the Question of the Migration of Mosquitoes. _Jour. Trop. Med. & Hyg._, 12, 1909, pp. 256-258, Sept. 1. Only fecundated females feed on blood, and must be fertilized after each batch of eggs. This determines largely the time and place of breeding.

SMITH, J.B. Concerning Migration of Mosquitoes. _Science_, 18, Dec. 11, 1903, pp. 761-764. Observations on the migrations of mosquitoes, particularly _C. sollicitans_.

MOSQUITO FIGHTING

CELLI, ANGELO. The Campaign Against Malaria in Italy. Transl. by J.J. Eyre. _Jour. Trop. Med. & Hyg._, XI, Apr. 1, 1908, pp. 101-108. Includes a good discussion of the effectiveness of destroying the mosquitoes in controlling malaria.

FELT, E.P. Mosquito Control. In _Report of the N.Y. State Entomologist for 1905_, pp. 109-116. Notes on importance and methods of control of various species.

GOLDBERGER, JOS. Prevention and Destruction of Mosquitoes. _Public Health Reports, Pub. Health and Mar. Hospt. Ser._, July 17, 1908. Life-histories and methods of fighting larvæ, pupæ and adults.

LE PRINCE, J.A. Mosquito Destruction in the Tropics. _Jour. Amer. Med. Assn._, LI, p. 26, Dec. 26, 1908. Occurrence and habits of _Anopheles_, methods of destruction. Results of anti-malarial work on the isthmus. Discussion by various doctors.

QUAYLE, H.J. Mosquito Control Work in California. _Bull. No. 178, Calif. Agric. Ex. Sta._, pp. 1-55, 1906. Habits and life-history of California species, with an account of experiments to control the salt-marsh species.

ROSENAN, M.J. Disinfection Against Mosquitoes with Formaldehyde and Sulphur Dioxid. _Hyg. Lab. Pub. Health and Mar. Hospt. Ser., Bull. 6_, 1901.

ROSS, RONALD. Mosquito Brigades and How to Organize Them. New York, 1902.

ROSS, RONALD. Logical Basis of the Sanitary Policy of Mosquito Reduction. _Science_, N.S., Vol. 22, No. 750, Dec. 1, 1905, pp. 689-699. Important article dealing with the methods of control.

SMITH, J.B. Salt-marsh Mosquitoes. _New Jersey Agric. Exper. Stn. Special Bulletin T_, 1902. Breeding-places and methods of control of this species.

SMITH, J.B. Mosquitocides. _Bull. 40, New Series U.S. Dept. Agric., Div. of Ento._, pp. 96-108, 1903. Results of experiments with a number of substances, several of which were found to be effective and some cheap enough to permit of their use to a limited extent.

SMITH, J.B. The New Jersey Salt-marsh and Its Improvement. _Bull. No. 207_, Nov. 14, 1907, _New Jersey Agric. Exper. Stn._ Results of draining the marshes to get rid of mosquitoes.

SMITH, J.B. The House Mosquito: a City, Town and Village Problem. _N.J. Agric. Ex. Stn. Bull. 216_, 1908. Work done on salt-marshes since 1904 practically eliminated the migratory species, so that _C. pipens_, the house mosquito, is now the problem. Life-history and methods of combating.

UNDERWOOD, W.L. Mosquitoes and Suggestions for Their Extermination. _Pop. Sci. Mo._, Vol. 63, 1903, pp. 453-466. Life-history, habits and methods of control.

UNDERWOOD, W.L. The Mosquito Nuisance and How to Deal with It. Boston, 1903.

First Antimosquito Convention, 1903. Pub., Brooklyn, 1904. Contains articles on what railroads, government and laws should do toward mosquito extermination; mosquito work in Havana; how state appropriations should be used, etc.

National Mosquito Extermination Society. Bulletin No. 1, 1904. Object of Society; brief sketches of Ross, Reed, and others. Reprints of a few articles on mosquito extermination.

American Mosquito Extermination Society. _Year Book for 1904-05._ N.Y., 1906. Containing reports of meetings and discussions of various problems. Several interesting papers, among them "Criminal Indictment of the Mosquito," F.W. Moss. "Mosquito Work at Panama Canal," W.C. Sorgas. "Diversities Among New York Mosquitoes," E.P. Felt. "Mosquito Extermination in New Jersey," J.B. Smith. "The Mosquito Question," Quitman Kohnke.

Antimalarial Work in the Panama Canal Zone. Editorial in _Jour. Trop. Med. & Hyg._, XI, Aug. 15, 1908, p. 251. Notes on the success of the measures adopted there.

MOSQUITOES AND DISEASE

DOTY, A.H. The Mosquito, Its Relation to Disease and Its Extermination. _New York State Journal of Medicine_, May, 1908.

FINLAY, CHAS. Mosquitoes Considered as Transmitters of Yellow Fever and Malaria. _Med. Record_, May 27, 1899, pp. 737-739. Review of his theory in regard to mosquitoes and disease and the probable necessary changes in view of recent discoveries.

HOWARD, L.O. Mosquitoes as Transmitters of Disease. _Review of Reviews_, XXIV, 1901, pp. 192-195. A review of the work of various investigators.

SMITH, J.B. Sanitary Aspect of the Mosquito Question. _Medical News_, Mar. 7, 1903. Note on mosquitoes and their relation to disease.

TAYLOR, J.B. Observations on the Mosquitoes of Havana, Cuba. Reprint from _La Revista de Medicina_, June, 1903, p. 27.

MALARIA

BANKS, C.S. Experiments in Malarial Transmission by Means of _Myzomyia ludlowii_. _Phil. Jour. Sci._, B. 2, 1907, pp. 513-535. Breeding-places of mosquitoes, life-histories of the species; mosquitoes and malaria.

CRAIG, C.F. Malarial Fevers. _Osler's Mod. Med._, Vol. I, p. 392, 1907. Historical; distribution; malarial parasites; classification; development; malarial mosquitoes; pathology; treatment, etc.

CRAIG, C.F. Studies in the Morphology of Malarial Plasmodia after the Administration of Quinine and in Intracorpuscular Conjugation. _Jour. Infec. Diseases_, VII, No. 2, 1910. See also same, IV, 1907, pp. 108-140. Gives the evidence upon which he bases his theory of the meaning of intracorpuscular conjunction.

CRAIG, C.F. The Malarial Fevers, Hemoglobinuric Fever and the Blood Protozoa of Man. N.Y., 1909. A thorough consideration of the subject of malaria and good discussion of the other subjects noted in title. Bibliography.

DEADERICK, W.H. Malaria. Philad., 1909. The chapter on ætiology treats of the transmission by mosquitoes.

HARRIS, S. Prevention of Malaria. _Jour. Amer. Med. Assn._, 53, Oct. 9, 1909, pp. 1162-67. Effects of malaria, transmission by mosquitoes, etc. In the discussion of the paper J.H. White summarizes the fight against yellow fever in New Orleans.

HERRICK, G.W. Relation of Malaria to Agriculture and Other Industries of the South. Economic losses occasioned by malaria; malaria responsible for more sickness among the white population than any other disease; relation to mosquitoes. _Pop. Sci. Mo._, Vol. 62, Apr., 1903, pp. 521-525.

JONES, ROSS, ELLETT. Malaria. London, 1907. Small book, introduction by Ross. Malaria in Greece and Italy; shows how this disease contributed to the downfall of great nations.

MANNABERG, JULIUS. Malaria. In Nothnagel's _Encyclopedia of Practical Med._, Amer. Ed., 1905, pp. 17-494. A very comprehensive discussion of the disease and the relation of mosquitoes to the malarial parasite.

MANSON, PATRICK. The Mosquito and the Malaria Parasite. _Brit. Med. Jour._, Vol. II for 1898, pp. 849-853. History of the parasite in the human and insect host; observations of Ross and others and their meaning.

MANSON, PATRICK. Experimental Demonstration of the Mosquito-malarial Theory. _Brit. Med. Jour._, Vol. 2 for 1900, pp. 949-951, also _Lancet_, II, 1900, pp. 923-925. Infected mosquitoes sent from Rome allowed to bite men in England who had not been in malarial regions. Malarial fever followed.

MANSON, PATRICK. Malarial Fever. Appendix to Vol. IX of T.C. Albutt's _System of Med._, 1900. Relation of the malarial parasite to the disease and to mosquitoes.

ROBERTSON, E.W. Renaming of Malaria--Anophelesis. _Va. Medical Semi-monthly_, Sept. 10, 1909. Considers malaria a misnomer and gives reasons for suggesting new name.

ROSS, RONALD. On Some Peculiar Pigmented Cells Found in Two Mosquitoes Fed on Malarial Blood. _Brit. Med. Jour._, 1897, Dec. 18, p. 1786. Records in his experiments in feeding mosquitoes on blood of malarial patients. Records finding the parasites in some of them. Important article.

ROSS, RONALD. Pigmented Cells in Mosquitoes. _Brit. Med. Jour._, 1898, Feb. 26, p. 550. Further notes on them.

ROSS, RONALD. The Mosquito Theory of Malaria. Report dated Calcutta, Feb. 16, 1899. Reprinted in _Pop. Sci. Monthly_, Vol. 56, Nov., 1899, pp. 42-46. Tells of his investigations in India and their results.

ROSS, RONALD. The Relationship of Malaria and the Mosquito. _Lancet_, II, 1900, July 7, p. 4880. Observation on the transmission of malaria.

ROSS, RONALD. Malaria Fever, Its Cause, Prevention and Treatment. London, 1902. Chapters on malaria, mosquitoes, prevention and treatment.

ROSS, RONALD. Parasites of Mosquitoes. _Jour. of Hyg._, VI, No. 2, Apr., 1906. Brief review of several of his earlier papers on this subject with additional notes.

SIMPSON, W.J.R. Recent Discoveries Which Have Rendered Antimalarial Sanitation More Precise and Less Costly. _Brit. Med. Jour._, 1907, II, pp. 1044-46. Discussion of the various factors in mosquito control.

STEPHENS, J.W.W., AND CHRISTOPHERS, S.R. The Practical Study of Malaria and Other Blood Parasites. London, 1908. Chapters on mosquitoes, flies and ticks and their relation to diseases.

STERNBERG, G.M. The Malarial Parasite and Other Pathogenic Protozoa. _Pop. Sci. Mo._, Vol. 50, 1897, pp. 628-641. Account of the discovery of the malarial parasite and more recent studies on it.

STERNBERG, G.M. Malaria. _Smith. Rept._, 1900, pp. 645-656. Review of the experimental evidence in support of the mosquito-malaria theory.

Malarial Fever. _Jour. Trop. Med. & Hyg._, II, Mar. 16, 1908, pp. 96-98. A list of literature mostly for the years 1906 and 1907.

YELLOW FEVER

ADAMS, S.H. Yellow Fever, a Problem Solved. The battle of New Orleans against the mosquito. _McClure's Magazine_, Vol. 27, June, 1906, p. 178. An interesting popular article.

CARROLL, JAMES. Yellow Fever. _Osler's Mod. Med._, Vol. II, 1907, p. 736. History, ætiology, treatment. A good review of the work of the Yellow Fever Com. and the results of their work.

CARROLL, JAMES. The Transmission of Yellow Fever. _Amer. Med. Assn._, 40, 1905, pp. 1429-33. Shows the relation of the mosquito to the disease.

CARROLL, JAMES. Yellow Fever. Lessons to be learned from the present outbreak of yellow fever. _Jour. of Amer. Med. Assn._, Vol. 45, 1905, pp. 1079-81. Among other things recommends that mosquitoes be kept from patients.

CHAILLE, S.E. The _Stegomyia_ and Fomites. _Amer. Med. Assn._, 40, 1903, pp. 1433-40. Concludes that the mosquito is the only proven disseminator of yellow fever. Extended discussion by various physicians.

DASTRE, A. The Fight Against Yellow Fever. _Smith. Rept._, 1905, pp. 339-350. History of the yellow fever epidemics, its geographical distribution, and the work that is being done to control it.

DOTY, A.H. On the Mode of Transmission of the Infectious Agent in Yellow Fever and Its Bearing upon the Quarantine Regulations. _Med. Record_, Oct. 26, 1901, pp. 649-653. Review of older theories in regard to the spread of yellow fever. Believes that the quarantines are now unnecessary.

FINLEY, CHAS. The Mosquito Theory of the Transmission of Yellow Fever and Its New Development. _Med. Record_, Jan. 19, 1901. Refers to his early observations on the subject, giving extracts from some of his earlier papers to show that he had long held the mosquito responsible for the dissemination of yellow fever.

GOLDBERGER, JOS. Yellow Fever, Ætiology, Symptoms and Diagnosis. _Yellow Fever Inst. Bull. 16, Pub. Health and Mar. Hospt. Ser._, 1907. Includes discussion of the relation of mosquitoes to the disease.

GUITERAS, JOHN. Experimental Yellow Fever at the Inoculation Station of the Sanitary Department of Havana. _Amer. Med._, Vol. II, No. 21, 1901, pp. 809-817. Experiments show that all types of the yellow fever from mild to severe may be produced by the bite of the mosquito.

MCFARLAND, JOSEPH. Life and Work of James Carroll. Memoir read at the fifth annual meeting of the Soc. of Tropical Med., 1908. Early life of Carroll and his work with the Yellow Fever Com.

PARKER, H.B., BEYER, G.E., AND POTHIER, O.L. Rept. of Working Party No. 1, Yellow Fever Institute. _Bull. 13, Pub. Health and Mar. Hospt. Ser._, 1903. As a result of their studies they believe that the disease is caused by a protozoan parasite which they name and describe. Discuss the relation of mosquitoes to the disease.

REED, WALTER; CARROLL, JAMES; AND AGRAMONTE, A. Experimental Yellow Fever. _Amer. Med._, July 6, 1901, pp. 15-23. Records of certain experiments and their results.

REED, WALTER; CARROLL, JAMES; AND AGRAMONTE, C.A. The Ætiology of Yellow Fever. A preliminary note presented at the Amer. Pub. Health Assn. _Philad. Med. Jour._, Oct. 27, 1900, pp. 790-796. Also an additional note in _Jour. Amer. Med. Assn._, 36, pp. 431-440, 1901. Records of their experiments and a summing up of the data in regard to yellow fever and the mosquito.

REED, WALTER, AND CARROLL, JAMES. The Prevention of Yellow Fever. _Med. Record_, Oct. 26, 1901, pp. 441-449. History of the disease, especially in U.S., results of the work of Yellow Fever Com. description, life-history and habits of the mosquito, its relation to yellow fever, methods of control. Important paper.

REED, WALTER. Recent Researches Concerning the Ætiology, Propagation and Prevention of Yellow Fever by U.S. Army Com. _Jour. Hyg._, 2, 1902, pp. 101-119. Review of work of the Yellow Fever Com. and the importance of the results. Bibliography.

ROSENAN, M.J., PARKER, H.B., FRANCIS, E., AND BEYER, G.E. Rept. of Working Party No. 2, Yellow Fever Institute. Experimental studies in yellow fever and malaria at Vera Cruz, Mex. _U.S. Pub. Health and Mar. Hospt. Ser._, May, 1904. Includes experiments and observations on mosquitoes.

ROSENAN, M.J., AND GOLDBERGER, JOS. Report of Working Party No. 3, Yellow Fever Institute. _Yellow Fever Inst. Bull. 15, Pub. Health and Mar. Hospt. Ser._, 1906. Unsuccessful attempts to grow the yellow fever parasite. Negative results in the experimental study of the hereditary transmission of the yellow fever in the mosquito. Appendix A gives a translation of Marchoux and Simonds' report in which they report positive results in their experiments along the same line.

STERNBERG, G.M. Transmission of Yellow Fever by Mosquitoes. _Smith. Rept._, 1900, pp. 657-673. Review of the early theories in regard to yellow fever and the work and findings of the yellow fever commission.

WHITE, J.H. Yellow Fever and the Mosquito. _Jour. Amer. Med. Assn._, LI, No. 26, Dec. 26, 1908. Considers both _S. calopus_ and _C. pungens_. Results of early mistakes. Necessity of destroying mosquito. Methods of destroying mosquito. Habits of mosquito.

Abstract of the Report of the French Yellow Fever Com. at Rio de Janeiro, 1903. _Pub. Health Report, Pub. Health and Mar. Hospt. Ser._, Vol. 19, Pt. I, p. 1019. A summary of their findings and conclusions to the date of report.

DE YBARRA, A.M.F. Yellow Fever Again in Cuba. _Jour. Trop. Med. & Hyg._, XI, Mar. 2, 1908, pp. 73-78. Cites a number of cases of yellow fever within the last few years and uses them as evidence to show that the disease may be transmitted in other ways than by the mosquito. A strong summing up of the arguments against the mosquito theory. Reprint of editorial in _Tex. Med. Jour._, Oct., 1907, also follows this article.

The Extinction of Yellow Fever at Rio de Janeiro. _Lancet_, II, 1909, p. 404. A review of a French publication giving the results of the work from 1903 to present time. In 1903 before work was begun there were 584 deaths from yellow fever. In 1908 only 4, and none so far in 1909. Success accredited to mosquito work and general sanitation.

A Pioneer in Research on Yellow Fever. Editorial in _Brit. Med. Jour._, May 30, 1908, p. 1306. Refers to the work of L.D. Beauperthuy, who, in 1853, set forth the theory that yellow fever was transmitted by mosquitoes.

DENGUE

ASHBURN, P.M., AND CRAIG, C.F. Experimental Investigations Regarding the Ætiology of Dengue Fever. _Jour. Infec. Diseases_, Vol. V, 1907, pp. 440-475. Conclude that the disease is spread only by mosquitoes.

COLEMAN, THOMAS D. Dengue. _Osler's Mod. Med._, Vol. II, 1907, p. 489. Ætiology, pathology, etc.; possibility of _Culex fatigans_ disseminating the disease.

GRAHAM, H. "The Dengue"; a Study of Its Pathology and Mode of Propagation. _Jour. of Trop. Med. & Hyg._, July 1, 1903, p. 209. Experiments which seem to show that dengue is transmitted by _Culex fatigans_.

LEICHTENSTERN, O. Dengue. In Nothnagel's _Encyclopedia of Practical Med._, Amer. Ed., 1905, pp. 720-743. Consideration of the disease and its transmission.

ROSS, E.H. The Prevention of Dengue Fever. _Amer. Trop. Med. & Parasit._, Vol. II, No. 3, July 1, 1908, pp. 193-195. A successful campaign against the mosquitoes in Port Said in 1906 stopped the outbreaks of malaria and dengue.

Dengue and Sand-flies. _Jour. Trop. Med. & Hyg._, 12, 1909, pp. 172-173. A note on these pages refers to the work of Dr. R. Doerr, who suspects that dengue may be carried by sand-flies, _Phlobotomus_, as well as by mosquitoes.

FILARIAL DISEASES AND ELEPHANTIASIS

CHRISTOPHERS, S.R. What Is Really Known of the Cause of Elephantiasis. _Ind. Med. Gaz._, Nov., 1907, p. 404. Questions Manson's theory in regard to the disease being caused by filaria.

MANSON, PATRICK. Tropical Diseases. London, 1908, pp. 594-648. A most comprehensive chapter on filariasis and elephantiasis.

PHALEN, J.M., AND NICHOLS, H.J. Filariasis and Elephantiasis in Southern Luzon. _Phil. Jour. Sci._, Sept., 1908. _Culex microannulatus_ regarded as the carrier of the filaria.

PROUT, W.T. On the Rôle of Filaria in the Production of Disease. _Jour. Trop. Med. & Hyg._, Apr. 1, 1908, p. 109. Discussion of same in same journal, June 1, 1908.

WHITE, DUNCAN. Filarial Periodicity and Its Association with Eosinophilia. _Jour. Trop. Med. & Hyg._, 12, July 15, 1909, pp. 175-183. Among other things he discusses the relation of mosquitoes to filarial diseases.

LEPROSY

BRINCKERHOFF, W.R. A Note upon the Possibility of the Mosquito Acting in the Transmission of Leprosy. _Pub. Health and Mar. Hospt. Ser._ (general publications), 1908. Suggests the possibilities of such transmission, but concludes that the probabilities are against it.

GOODHUE, E.S. The Bacillus Lepræ in the Gnat and Bedbug. _Ind. Med. Gaz._, Vol. XLI, Aug., 1906, p. 342. Has found this bacillus in mosquitoes and bedbugs, but believes the latter is more concerned in transmitting the disease.

GOODHUE, E.S. Mosquitoes and Their Relation to Leprosy in Hawaii. _Amer. Med._, N.S., 2, 1907, p. 593. Suggests that mosquitoes may carry the disease, also warns against danger from flies and bedbugs.

HUTCHINSON, J. Mosquitoes and Leprosy. _Brit. Med. Jour._, Dec. 22, 1906, Vol. II, p. 1841. Evidence against the insect theory of transmission of leprosy.

MUGLISTON, T.C. On a Possible Mode of Communication of Leprosy. _Jour. Trop. Med._, Vol. VIII, July 15, 1905, p. 209. Suggests that the itch-mite may be the carrier of leprosy. Studies on 77 lepers led him to this conclusion.

SMYTH, W.R. Leprosy. _Brit. Med. Jour._, Dec. 8, 1906, Vol. II, p. 1670. Believes that bedbugs or some similar wingless parasite conveys the disease.

PLAGUE

BRANNERMAN, W.B. Spread of Plague in India. _Jour. of Hyg._, Vol. 6, No. 2, Apr., 1906, pp. 179-211. A digest of experiments made in India. Discusses various ways in which the disease may be spread. Review of the evidence that insects may be concerned. Bibliography.

CALVERT, W.J. Plague. _Osler's Mod. Med._, Vol. II, 1907, p. 760. History; bacteriology; pathology; plague among animals; transmission, etc.

HAM, B. BURNETT. Report on Plague in Queensland, 1900-1907. P. 153 discusses the rat-flea theory of dissemination of bubonic plague, summing up the evidence of various observers, including the Indian Advisory Com. and others. Considers the evidence conclusive that _P. cheopis_ and possibly _C. fasciatus_ transmit plague. Other pages discuss various rat fleas and their relation to plague in rats.

HANKIN, E.H. On the Epidemiology of Plague. _Jour. Hyg._, 5, 1905, pp. 48-83. A comprehensive discussion of the disease and its spread, several pages devoted to rats and fleas; evidence for and against the theory that rats and fleas are the principal carriers of the disease.

HERZOG, MAX. The Plague, Bacteriology, Morbid Anatomy & Histopathology, Including the Consideration of Insects as Plague Carriers. Biological Laboratory Bureau of Govt. Laboratories, Manila, Oct., 1904. Reviews the evidence regarding the possibility of fleas carrying plague; describes a new rat flea (_Pulex philippinensis_); records experiments with fleas and cites a case of bubonic plague in a child in which the infection was possibly carried by _Pediculi_.

MCCOY, G.W. Plague Bacilli in Ectoparasites of Squirrels. _Pub. Health Reports, Pub. Health and Mar. Hospt. Ser._, Vol. XXIV, No. 16, Apr. 16, 1909. Experiments with fleas and lice from infected squirrels demonstrating presence of plague bacilli.

MCCOY, G.W. The Susceptibility of Gophers, Field-mice and Ground-squirrels to Plague Infection. _Jour. of Infec. Diseases_, Vol. 6, 1909, No. 3, pp. 283-288. Gophers highly resistant, field-mice moderately susceptible and ground-squirrels very susceptible to plague.

MITZMAIN, M.B. Insect Transmission of Bubonic Plague: a Study of the San Francisco Epidemic. _Ento. News_, 19, No. 8, 1908, pp. 353-359. Fleas obtained in examination of 1,800 rats. Attempt to locate source of rat and flea introduction.

MORTON, F.M. Eradicating Plague from San Francisco. Report of the Citizens' Health Com. and an account of its work. San Francisco, 1909. Discusses the epidemics, methods of transmission, methods of fighting, etc.

RUCKER, W.C. Plague Among Ground-squirrels in Contra Costa Co., Cal. _Pub. Health Reports, Pub. Health and Mar. Hospt. Ser._, Aug. 27, 1909. Reports of human cases supposed to be connected with plague among ground-squirrels. Plague among squirrels; habits, methods of fighting, etc.

RUCKER, W.C. Fighting an Unseen Foe. _Sunset Mag._, XXII, No. 2, Feb., 1909. Story of the fight against plague in San Francisco.

SHIPLEY, A.E. Rats and Their Animal Parasites. _Jour. Eco. Biology_, Vol. III, No. 3, Oct. 28, 1908. List of species of ecto- and endoparasites.

SIMPSON, W.J. A Treatise on Plague. Cambridge Univ. Press, London, 1906. Deals with historical, epidemiological, clinical, therapeutic and preventive aspect of the disease.

THOMPSON, J.A. The Mode of Spread and Prevention of Plague in Australia. _Lancet_, Oct. 19, 1907, p. 1104. Rat fleas the essential factor in transmitting plague, and preventive methods should be directed against the rats.

THOMPSON, J.A. On the Epidemiology of Plague. _Jour. Hyg._, Vol. VI, No. 5, Oct., 1906. Methods of infection, spread, relation of rats to the disease and a review of the rat-flea theory. Bibliography.

VERJBITSKI, D.T. The Part Played by Insects in the Epidemiology of Plague. _Jour. Hyg._, 8, 1908, No. 2, pp. 162-208. Record of extensive experiments with fleas. Fleas communicated plague for three days, bedbugs for five days. Interrelation of fleas, rats, dogs, cats, and man. An important article translated from Russian.

WHERRY, W.B. Further Notes on the Rat Leprosy and on the Fate of the Human and Rat Leper Bacillus in Flies. _Jour. Infec. Diseases_, Vol. 5, No. 5, 1908. Discussion and references, experiments with flies, summary, etc. More than 1,115 lepra-like bacilli were counted in a single fly-speck.

WHERRY, W.B. Plague Among the Ground-squirrels of California. _Jour. Infec. Diseases_, Vol. 5, No. 5, 1908, pp. 485-533. How the plague was first discovered among rats, records of cases and a discussion of the possible relation of this to human plague cases.

Eradicating Plague in San Francisco; Report of the Citizens' Health Committee, 1909. An account of the recent outbreaks and the methods of fighting them.

Report of the Indian Plague Commission, Vol. V, pp. 75-77, 1901. In these pages the Commission considers the question of the transference of plague by suctorial insects. It considers Simonds' claims and others and believes that "suctorial insects do not come under consideration with the spread of plague."

Reports on Plague Investigations in India Issued by the Advisory Committee Appointed by the Sec. of State for India, the Royal Society and the Lister Institute. The reports include the reports of the Working Commission appointed by the Advisory Committee and reports on various contributory investigations. They are published in the _Jour. of Hygiene_ as "Extra Plague Numbers." All these reports deal very largely with the relation of the rat and flea to plague, and are commonly referred to as "Reports of Indian Plague Commission." The first number, Vol. VI, Sept., 1906, contains articles on "Experiments upon the Transmission of Plague by Fleas." "Note on the Species of Fleas Found on Rats, _Mus rattus_ and _Mus decumanus_ in Different Parts of the World." "The Physiological Anatomy of the Mouth-parts and Alimentary Canal of the Indian Rat Flea, _Pulex cheopis_," and other papers on the relation of rats to plague. The second number, Vol. VII, July, 1907, contains articles on "On the Significance of the Locality of the Primary Bubo in Animals Infected with Plague in Nature," "Further Observations on the Transmission of Plague by Fleas with Special Reference to the Fate of Plague Bacillus in the Body of the Rat Flea," "Experimental Production of Plague Epidemics Among Animals," "Experiments in Plague Houses in Bombay," "On the External Anatomy of the Indian Rat Flea and Its Differentiation from Some Other Common Fleas," "A Note on Man as a Host of the Indian Rat Flea," and others on the relation of rats to plague. The third number, Vol. VII, Dec., 1907, contains articles on "Digest of Recent Observations on the Epidemiology of Plague" (Bibliography), "Epidemiological Observations in Bombay City," "Epidemiological Observations in the Villages of Wadhala, Parel, Worli in the Neighborhood of Bombay Village," "General Considerations Regarding the Spread of Infection, Infectivity of Houses, etc., in Bombay City and Island," "Epidemiological Observations in the villages of Dhand and Kasel (Punjab)." The fourth number, Vol. VIII, May, 1908, contains articles on "The Part Played by Insects in the Epidemiology of Plague" (see also ref. under D.T. Verjbitski), "Observations on the Bionomics of Fleas with Special Reference to _P. cheopis_," "The Mechanism by Means of Which the Flea Cleans Itself of Plague Bacilli," "On the Seasonal Prevalence of Plague in India."