Part 44

The plant poisons are more frequently due to inherent injurious substances, although even among them, bacterial and fungus diseases play an important rôle. Among the 16,673 plants indigenous to North America, almost 500 are more or less poisonous and about 30 are of great economic importance. The toxic factor may be confined to the leaf, seed or root, but more often it is associated with all parts of the plant. Through the efforts of the Department of Agriculture a more or less complete list of the plants implicated in the poisoning of stock has been compiled. This list includes the following: _Amanita muscaria_; _A. phalloides_; _Veratrum viride_; _Phytolacca decandra_; _Agrostemma githago_; _Delphinium_, 25 varieties; _Astragalus mollissimus_; _Aragallus lambertii_; _Crotalaria sagittalis_; _Euphorbia lathyris_; _E. marginata_; _Rhus radicans_; _R. diversiloba_; _R. vernix_; _Aesculus pavia_; _A. hippocastanum_; _A. glabra_; _A. Californica_; _Cicuta maculata_; _C. vagans_; _Conium maculatum_; _Kalmia latifolia_; _K. augustifolia_; _Leucothöe catesbaei_; _Rhododendron maximum_; _Pieris mariana_; _Datura stramonium_; _Solanum nigrum_; _S. dulcamara_; _Helenium autumnale_; _Asclepias pumila_; _A. verticullata_; _A. galoides_; _A. mexicana_; _A. eriocarpa_; _A. speciosa_; _A. fremonti_; _Eupatorium agertoides_; _E. urticarfolium_; _Isocoma wrightii_; _Daubentonia longifolia_; _Senecio jacobia burchelli latifolius_.[89] Some of these as the Amanita are only occasional sources of disaster, but as they frequently involve man they are important. The _Amanita muscaria_ symptoms appear very soon after eating the fungus and consist of a deepening stupor. _A. phalloides_, on the contrary, starts with severe abdominal pain, cramps, discharges of blood and mucus and later convulsions. The meat of animals dying from fungus poisoning is distinctly poisonous. This transfer of poison to the muscles of the animal partaking of these plants occurs also in poisoning with Kalmia.

The other plants of this list are closely associated with the grass foods and are consumed usually when the food on a range is scarce. Some groups as the Asclepias contain a distinct neurotoxin and give rise to a condition known as trembles or staggers. It affects mostly cows and sheep, causing staggering, trembling gait, bloating and salivation and death with convulsions. There is marked congestion of alimentary tract, liver and kidney. In the cerebrospinal axis there are marked changes in the nerve cells of the medulla and spinal cord. The Purkinje cells show the effect of extreme fatigue. Other plants causing stiffness or weakness of the extremities, show on microscopic examination no definite lesions in the cerebrospinal axis. Loco weed—_Astragalus mollissimus_ and _Aragallus lambertii_—causes maniacal disturbances but no gross lesions. This weed in Colorado costs the state enormous amounts of money yearly.

Helenium poisons domestic animals by means of a toxic glucoside, dugaldin, which produces stiffness, salivation and nausea with mild depression (“spewing sickness”). The alimentary tract shows severe inflammation of the rumen and reticulum which may at times be hemorrhagic. The liver usually presents an interstitial hepatitis. This toxin is decidedly hemolytic. The effects of this plant are always permanent, total recovery being very rare.

The larkspur (25 different varieties), on the contrary, shows prompt recovery after treatment, but no establishment of toleration. These plants give rise to nausea, vomiting and great agitation and destroy many animals yearly. The poisons are included in four alkaloids, all spinal cord depressants resembling aconite in general character.

These poisonous plants all produce more or less gastrointestinal inflammation and practically all are destructive in their action on the liver, pancreas and kidney. It is impossible to form even approximate estimates of the damage done by them because of the general ignorance of the subject. The Division of Botany has been collecting for the past few years specific information concerning these plants, but the individual plants are not equally poisonous, and all animals do not show the same susceptibility to the poison. _Veratrum viride_, for instance, is eaten with relish by sheep and elk and is decidedly toxic for the horse. In many the toxic factor has not been isolated. Some, as Euphorbia, are poisonous only when fed in honey derived from its flowers.

The influence of diet on the general health of animals is very far reaching and very inclusive. Metabolic disturbances are undoubtedly at times the result of unbalance—deficiencies on the one side, excesses on the other, at times are probably much more the results of bacterial invasions aided and abetted by the food administered, at still other times are poisonous either in their own content or from the degradation products resulting from digestion or bacterial decomposition.

SECTION XVI NEOPLASMS

The occurrence of true neoplasms in domesticated animals has always been well known and thoroughly studied while for beasts in the wild the data has been fragmentary. That tumors exist in natural environment has been accepted upon the testimony of hunters but there is an impression, and nothing more, of their extreme scarcity probably because only younger vigorous animals come to the attention of the sportsman or collector. This matter will of course not be settled until some natural historian with a knowledge of pathology, makes a survey of a large number of specimens taken during a collecting expedition. Observations in menageries are valuable to the extent that they show what tumors may occur, the orders most commonly affected and the incidence under captive conditions. It is unfortunate that too seldom do we know the history of our specimens in regard to the age, manner of capture or breeding, data which if at our disposal would permit of a very fair idea of the probable incidence in the wild and of the effect of captivity. Some observations in this direction are however possible by using the figures of known captivity and breeding.

The facts gleaned from a study of neoplasms under captive conditions may be of interest to the experimental pathologist, especially when considering the relation of the origin from the embryological layers. I have tabulated this with great care, using Jordan’s[90] table for the source of the various tissues, and further have studied the destination of metastatic emboli in terms of the blastoderm.

The following observations are based entirely upon our own data for while it might be valuable to include the cases in the literature their descriptions are often so meagre that they would not combine readily with our records. Plimmer, Seligmann, and Murray have published in the _Proceedings of the London Zoological Society_ since 1903, their annual report of the pathological service in which they have recorded very many interesting tumors. So too from time to time Harlow Brooks and W. R. Blair in the _Annual Report of the New York Zoological Park_, have presented cases occurring in their service. Joest [91] discusses tumors in the lower animals in a broad way and analyzes their incidence and characters. C. Y. White and I [92] have already published articles on this subject. Numerous single references may be found in the _Jahresber. der Veterinär-Medicin_.

In so far as the incidence of tumors in wild animals is concerned this literature can scarcely give an adequate measurement but it would seem that they are less than in domestic varieties. Exact figures for the occurrence of tumors in the latter seem not available in the literature, but one can find that in the Prussian army horses about one hundred are observed each year. In our 5,365 specimens collected during nineteen years, 94 tumors in 92 animals have been found, 1.7 per cent. or about one in every sixty specimens, not at all a low figure. If one were to include all fibromata of the feet and the blood collections to which the name angioma might be applied, this incidence would be greater; they are excluded because few in number and vague in history; only one true angioma was seen.

The gross and microscopical appearances of tumors in the lower animals are essentially the same as one encounters in human beings or at least it is possible to apply the pathological nomenclature used in human medicine to all the neoplasms we have discovered. There is appended a list of all the animals and their tumors, a table of zoological orders, tumors and organs (Table 21) and an analytical table of the histological data. (Table 22)

TABLE 21. _Table of Orders and Families Showing Type of Tumor and Principal Organ of Origin._

═══════════════════╤═══════╤═══════╤═════════╤══════╤══════════╤══════ Order Family │Fibroma│Osteoma│Chondroma│Lipoma│Myoma and │Glioma │ │ │ │ │Fibromyoma│ │ │ │ │ │ │ ───────────────────┼───────┼───────┼─────────┼──────┼──────────┼────── „ „ │ „ │ „ │ „ │ „ │ „ │ „ │ │ │ │ │ │ ───────────────────┼───────┼───────┼─────────┼──────┼──────────┼────── Primates, │ │ │ │ │ │ Cercopithecidæ │ │ │ │ │ │ Cebidæ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ Lemures, Lemuridæ │ │ │ │ │ │ │ │ │ │ │ │ Carnivora, Felidæ │ │ │ 1│ │ │ │ │ │ │ │ │ Viverridæ │ │ │ │ │ │ Canidæ │ │ │ │ │ │ Procyonidæ │ │ │ │ │ │ Ursidæ │ │ │ │ │ │ │ │ │ │ │ │ Phocidæ │ │ │ │ │ │ │ │ │ │ │ │ Rodentia, Sciuridæ │ │ 1│ │ │ │ Muridæ │ │ │ │ │ │ Heteromyidæ │ │ │ │ │ │ │ │ │ │ │ │ Octodontidæ │ │ │ │ │ │ Hystricidæ │ │ │ │ │ │ Dasyproctidæ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ Proboscidea │ │ │ │ │ 1│ Ungulata, Equidæ │ 1│ │ │ │ │ Bovidæ │ │ │ │ │ 1│ Cervidæ │ │ │ │ │ │ Camelidæ │ │ │ │ │ │ Suidæ │ │ │ │ │ │ Edentata, │ │ │ │ │ 1│ Dasypodidæ │ │ │ │ │ │ Marsupialia, │ │ │ │ │ │ Didelphyidæ │ │ │ │ │ │ Dasyuridæ │ │ │ │ │ │ Peramelidæ │ │ │ │ │ │ Macropodidæ │ │ │ │ │ │ Passeres, Turdidæ │ │ │ │ │ │ Crateropodidæ│ │ │ │ │ │ Tanagridæ │ │ │ │ 1│ │ Fringillidæ │ │ │ │ 1│ │ Icteridæ │ │ │ │ │ │ Striges, Bubonidæ │ │ │ │ │ │ Psittaci, Loridæ │ │ │ │ │ │ Cacatuidæ │ │ │ │ 2│ │ Psittacidæ │ │ │ │ 3│ │ 1 │ │ │ │ │ │ Accipitres, │ │ │ │ 1│ │ Falconidæ │ │ │ │ │ │ Columbæ, Columbidæ │ │ │ │ │ │ Galli, Phasianidæ │ │ │ │ │ │ Fulicariæ, Rallidæ │ │ │ │ │ │ Anseres, Anatidæ │ 1│ │ │ │ │ Struthiones, Rheidæ│ │ │ │ │ │ ───────────────────┼───────┼───────┼─────────┼──────┼──────────┼────── Total │ 2│ 1│ 1│ 8│ 3│ 1 ───────────────────┴───────┴───────┴─────────┴──────┴──────────┴──────

═══════════════════╤═══════╤════════════╤═══════╤═════════╤═══════════ Order Family │Angioma│Endothelioma│Sarcoma│Papilloma│Epithelioma │ │ │ │ │ │ │ │ │ │ ───────────────────┼───────┼────────────┼───────┼─────────┼─────────── „ „ │ „ │ „ │ „ │ „ │ „ │ │ │ │ │ ───────────────────┼───────┼────────────┼───────┼─────────┼─────────── Primates, │ │ │ │ │ Cercopithecidæ │ │ │ │ │ Cebidæ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ Lemures, Lemuridæ │ │ │ │ │ │ │ │ │ │ Carnivora, Felidæ │ 1│ 1│ │ │ │ │ │ │ │ Viverridæ │ │ │ │ │ Canidæ │ │ │ 1│ │ Procyonidæ │ │ │ │ │ Ursidæ │ │ │ │ │ 1 │ │ │ │ │ Phocidæ │ │ │ │ │ │ │ │ │ │ Rodentia, Sciuridæ │ │ │ │ │ Muridæ │ │ │ 2│ │ Heteromyidæ │ │ │ 1│ │ │ │ │ │ │ Octodontidæ │ │ │ 1│ │ Hystricidæ │ │ │ │ │ Dasyproctidæ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ Proboscidea │ │ │ │ │ Ungulata, Equidæ │ │ │ │ │ Bovidæ │ │ │ 1│ │ Cervidæ │ │ │ │ │ Camelidæ │ │ │ │ │ Suidæ │ │ │ │ │ Edentata, │ │ │ │ │ Dasypodidæ │ │ │ │ │ Marsupialia, │ │ │ │ │ Didelphyidæ │ │ │ │ │ Dasyuridæ │ │ │ │ │ 1 Peramelidæ │ │ │ │ │ Macropodidæ │ │ │ │ │ Passeres, Turdidæ │ │ │ │ │ Crateropodidæ│ │ │ │ │ Tanagridæ │ │ │ │ │ Fringillidæ │ │ │ │ │ Icteridæ │ │ │ │ │ Striges, Bubonidæ │ │ │ │ 1│ Psittaci, Loridæ │ │ │ │ │ Cacatuidæ │ │ │ │ │ Psittacidæ │ │ │ 7│ │ 1 │ │ │ │ │ Accipitres, │ │ │ 1│ │ Falconidæ │ │ │ │ │ Columbæ, Columbidæ │ │ │ 1│ │ Galli, Phasianidæ │ │ │ │ │ Fulicariæ, Rallidæ │ │ 1│ │ │ Anseres, Anatidæ │ │ │ 1│ │ Struthiones, Rheidæ│ │ │ │ │ ───────────────────┼───────┼────────────┼───────┼─────────┼─────────── Total │ 1│ 2│ 16│ 1│ 3 ───────────────────┴───────┴────────────┴───────┴─────────┴───────────

═══════════════════╤═══════╤═════════╤═══════════╤═════════════╤══════ Order Family │Adenoma│Carcinoma│ Chorion- │Hypernephroma│Mixed │ │ │epithelioma│ │Tumors │ │ │ │ │ ───────────────────┼───────┼─────────┼───────────┼─────────────┼────── „ „ │ „ │ „ │ „ │ „ │ „ │ │ │ │ │ ───────────────────┼───────┼─────────┼───────────┼─────────────┼────── Primates, │ 1│ │ │ │ Cercopithecidæ │ │ │ │ │ Cebidæ │ │ │ │ 1│ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ │ Lemures, Lemuridæ │ 1│ │ │ │ │ │ │ │ │ Carnivora, Felidæ │ 2│ 1│ │ │ │ │ │ │ │ Viverridæ │ │ 2│ │ │ Canidæ │ 3│ 1│ │ │ 1 Procyonidæ │ 1│ │ │ │ Ursidæ │ │ 2│ │ │ │ │ │ │ │ Phocidæ │ │ │ │ 1│ │ │ │ │ │ Rodentia, Sciuridæ │ 1│ │ │ 1│ Muridæ │ │ 3│ │ │ Heteromyidæ │ │ │ │ │ │ │ │ │ │ Octodontidæ │ │ │ │ │ Hystricidæ │ │ │ 1│ │ Dasyproctidæ │ │ 1│ │ │ │ │ │ │ │ │ │ │ │ │ Proboscidea │ │ │ │ │ Ungulata, Equidæ │ │ │ │ │ Bovidæ │ │ │ │ │ Cervidæ │ 1│ │ │ │ Camelidæ │ │ 1│ │ │ Suidæ │ │ 1│ │ │ Edentata, │ │ │ │ │ Dasypodidæ │ │ │ │ │ Marsupialia, │ 1│ 1│ │ │ Didelphyidæ │ │ │ │ │ Dasyuridæ │ │ 1│ │ │ Peramelidæ │ │ 1│ │ │ Macropodidæ │ │ 2│ │ │ Passeres, Turdidæ │ │ │ │ 1│ Crateropodidæ│ 1│ │ │ │ Tanagridæ │ │ │ │ │ Fringillidæ │ │ 2│ │ │ Icteridæ │ │ │ │ 1│ Striges, Bubonidæ │ │ │ │ │ Psittaci, Loridæ │ │ 1│ │ │ Cacatuidæ │ │ │ │ │ Psittacidæ │ 5│ 4│ │ 1│ 1 │ │ │ │ │ Accipitres, │ │ │ │ │ Falconidæ │ │ │ │ │ Columbæ, Columbidæ │ │ │ │ │ Galli, Phasianidæ │ │ 1│ │ │ Fulicariæ, Rallidæ │ │ │ │ │ Anseres, Anatidæ │ 1│ │ │ 1│ Struthiones, Rheidæ│ 1│ │ │ │ ───────────────────┼───────┼─────────┼───────────┼─────────────┼────── Total │ 19│ 25│ 1│ 7│ 2 ───────────────────┴───────┴─────────┴───────────┴─────────────┴──────