Chapter 8

SOURED MILK IN HEALTH AND DISEASE

When people are ill the best thing they can do is to place themselves in the hands of the doctor, who will try to regulate their lives, including their diet, in accordance with the conditions which science suggests as the most likely to lead to their recovery.

It is not the aim of this book to teach persons who should be under medical treatment to doctor themselves; soured milk may or may not be beneficial in their case--that is for the medical man to say; and further, if it should be beneficial the doctor ought to have its preparation under his control. Slight differences in quality and purity may count for much in cases of acute disease, differences which might not matter to the person who requires no medical attention, and who consumes the article as a health-giving food. A considerable body of evidence is already on record as to the potency in certain cases of soured milk as a curative agent, and it seems to have taken its place in medicine as a recognised remedy.

There is a wide field of usefulness, however, outside of the strictly medical one. Professor Metchnikoff has collected many striking examples of individuals and peoples inhabiting different parts of the world, who thrive, and in many cases attain to a great age, and whose diet consists largely of soured milk. He has made a wide and general inquiry into the causes which tend to shorten life, and makes out a strong case in support of the view that in many cases this is the result of what is called auto-intoxication or self-poisoning. In man and in the mammalia generally, the colon or large intestine is very largely developed; this organ is not of much value in the digestion of food, and seems to be chiefly a receptacle for waste material; it is, as a rule, extremely rich in bacterial flora, which produce putrefactive changes in the waste material. As a result various poisonous principles are evolved, and these find their way into the blood, accompanied frequently, there is every reason to believe, by the injurious bacteria themselves. In this way many diseases and ailments are produced which shorten life. The inquiry then naturally turns to what is the best way of dealing with this state of matters. It is known that the bacteria referred to flourish best in alkaline or at least non-acid surroundings, and it is known that these conditions very frequently exist in the large intestine. Acids are the best antiseptics; they have been used from time immemorial as preservatives; pickles are preserved in vinegar or acetic acid, and when milk is allowed to sour under proper conditions, the germs of putrefaction are destroyed or their activity inhibited, and it keeps a considerable time. Doubtless, in hot countries, it was this property of lactic acid which first led to milk being artificially soured with a view to its preservation as an article of food. So powerful is lactic acid in this respect that it is a custom in some countries to preserve meat by placing it in soured milk.

How can acids be applied so as to control the bacterial flora of the large intestine? Not in the ordinary way, because, when administered through the mouth, they are used up long before they can penetrate to the colon. The brilliant idea occurred to Professor Metchnikoff, of administering acid-producing germs which might work their way through the digestive system, and, reaching the large intestine, produce the acid required. After much experimenting the bacillus of Massol, _Bacillus bulgaricus_, was adopted as the most suitable. The Bulgarian bacillus is an extremely vigorous one, multiplying with great rapidity, and persisting in conditions that would be inimical to other microbes. The growth and development of bacteria is interfered with by the products of their own activity; thus, ordinary lactic-acid-producing organisms die when a certain amount of lactic acid has been developed; the same fate overtakes the Bulgarian bacillus, but it survives longer and is able to produce as much as two and one half per cent. of lactic acid in milk before it ceases operations. It seemed therefore the most likely to be able to survive the journey through the digestive system. Experiments fully bore out this supposition, as no great difficulty was encountered in naturalising the Bulgarian bacillus in the large intestine, not only in milk cultures, but grown in solution of malt, bouillon, etc. It thrives in all kinds of sugar, and therefore can be administered in a variety of media, very beneficial results following in many cases. Direct tests showed a large reduction of the injurious intestinal flora when the Bulgarian bacillus had been naturalised in the colon, and the bacillus persisted long after it had ceased to be administered. Specialists who have taken up the subject report the cure of many ailments through the agency of soured milk, and it seems to have entered upon a lengthening career of medical usefulness.

The fact of so many old people being found in countries where soured milk is a staple of diet naturally raises the question as to whether its general use in other countries might not have a beneficial effect on health and longevity. Its usefulness as a remedial agent in certain diseases is already demonstrated; is there not a strong probability, amounting almost to a certainty, that its consumption by people in health would tend to ward off many ailments and prolong life? Of course there will be some for whom it is not suitable; there are people who cannot eat strawberries without discomfort, but no one thinks of prohibiting the general use of the fruit on that account. In the matter of diet the person in health, if he exercises ordinary care, may be left to find out for himself what suits him. The soured milk remedy is not a disagreeable one, as, when properly prepared, the article forms both a pleasant and refreshing article of diet. The question of getting the right article, however, is a very important one. Milk is a splendid rearing ground for many bacteria, some of which are very injurious; among these may be pathological germs, the seeds of tuberculosis, enteritis, etc. The danger with soured milk is, that in the process of culture we develop the best condition for the increase of these when they preponderate, or when, through the use of bad cultures, the lactic-acid-producing bacteria are absent, or present only in small numbers. By the thorough boiling of the milk, we get rid of all living bacteria and nearly all spores or germs, and by scrupulous cleanliness in the vessels used--scalding or even boiling them, and allowing them to dry naturally in an inverted position--we greatly diminish the probability of infection with fresh injurious germs from the atmosphere. All depends on the purity of the culture employed; this can now be obtained, prepared in the most careful manner, from wholesale chemists making a speciality of its manufacture.

As we have seen, even the Bulgarian bacillus is ultimately killed by the products of its own activity, and the natural corollary is, that the life of cultures cannot be a long one. Only those cultures should be bought which are labelled with the date to which they are guaranteed to maintain their efficiency. With fresh good milk, careful boiling, scalding, and cleanliness with regard to the containing vessels, and the means of maintaining the incubating temperature for ten or twelve hours, there is not the slightest difficulty in preparing perfectly reliable soured milk. There are simple tests which will sufficiently guide the experimenter; the soured milk should not be too acid to the taste, and it has a flavour of its own by which its quality can be recognised. The litmus test-papers mentioned in the chapter on the chemistry of milk are very useful; both the red and the blue papers should be obtained and used first of all in testing the quality of the fresh milk. After incubation the soured milk should turn the blue paper decidedly red; if this does not occur, test it with the red paper; if the latter turns blue it is proof that the wrong fermentation has taken place--that putrefactive germs have gained the upper hand. The most probable explanation is, that the culture is bad, the Bulgarian bacillus is not present, or if so, only in small numbers. With these simple tests, combined with proper care, one cannot go far wrong. The Eastern nations who prepare soured milk in various forms do not exercise the care we have predicated, but they seem to make the article of fairly constant and good quality. It has been suggested in explanation that, as the ordinary flora differs in different countries, the bacterial flora varies in a similar manner, and that in these Eastern countries injurious bacteria are not so prevalent in the atmosphere as they are with us.

It is also said that the flavour of the soured milk prepared in Bulgaria is quite different from that prepared in Paris, London, or New York; one reason probably is that the "maya" or ferment used in Bulgaria contains several other organisms besides the Bulgarian bacillus, which raises the question whether a pure culture of one bacillus is the best to use.

Professor Metchnikoff found that this bacillus alone had certain defects; it attacks fat and is apt to give a tallowy taste when cream is present in the milk. He therefore associated with it another lactic-acid-producing organism, and this combination is the basis of his culture called "lactobacilline." The presence of yeasts, which occur in the Eastern ferments, has been advocated by some; the yeast in association with the lactic organisms produces a small amount of alcohol. The question of the composition of the culture will have to be fought out by the experts, but meantime, if we go to the right source, we have good enough cultures to go on with.

A good deal can be said for the use of skimmed or separated milk instead of whole milk. Cream as a rule contains far more bacteria than the rest of the milk, and we therefore start from a surer foundation when it is removed; besides, the mechanical separator, now so largely used, removes slime and other impurities from the milk, and these also are hotbeds of bacteria.

Soured milk may be taken at any time, the first thing in the morning, before or after meals, or the last thing at night. The quantity will vary with the individual, but from half a pint to a pint is a fair amount for daily use. If one wishes to have the maximum effect it is necessary for the time being to curtail the use of butcher's meat and substitute fish, yolk of eggs, and other similar foods; not much alcohol should be taken, and smoking might be reduced to a minimum. Those who cannot take even skimmed milk may use whey in which to cultivate the bacillus; it is not desirable to employ the whey which has been separated by the use of rennet, as in cheese- or junket-making. A better article is obtained by adding a very small quantity of pure hydrochloric acid to milk which has been boiled, and then filtering through a sieve, which retains the curd while the liquid whey passes through; a pinch of soda is added to neutralise the excess of acid, and, after boiling, the liquid should turn red litmus paper blue; it is then ready for the addition of the culture and incubation in the same manner as with milk. A solution of malt--the extract dissolved in hot water is convenient--may also be used instead of milk, and strongly malted bread or biscuits are excellent to take with the soured milk or cultures in other mediums, to supply food for the bacillus in the form of malt sugar. Other sugars, cane or grape, are also very useful, and may be taken in the form of fruit juices, syrups, confections, jams, sweet puddings, etc.

We lay stress on the use of soured milk or other cultures of the Bulgarian bacillus by people in health as a probable preventive of disease and a possible agent in the lengthening of life, but it may be of interest to give a short account of its use by medical men in the treatment of various ailments. An English authority on the subject, Dr. Herschell, states that the symptoms of the poisoning of the system by the toxic substances produced by injurious bacteria in the large intestine may include headaches, misery and depression of spirits, drowsiness and stupor, giddiness, dimness of sight and dizziness, fatigue without obvious cause, both of the muscles and brain, fear, panic, and nervousness, disagreeable sensations in the limbs or face, such as numbness, tingling, or prickling, crawling sensation of weight or of heat or cold, dyspepsia of the sort where there is a deficiency of hydrochloric acid and pepsin in the gastric juice, accompanied by flabbiness and loss of power in the muscles of the stomach, and characterised by flatulence, nausea, loss of appetite, with discomfort and weight after food, furred tongue, emaciation, earthy colour of the skin, offensive perspiration and the other signs of biliousness, enlargement of the liver, and anæmia. These symptoms may have other causes, and when one or several of them are present a chemical and physical examination of the urine and fæces is necessary to prove that they have resulted from auto-intoxication. When this is shown the soured milk treatment is indicated, and many striking cures are detailed as witnesses to its efficacy. The liver and kidneys are the natural guardians of the body against the toxines we are speaking of, and frequently they are over-strained; the soured milk treatment greatly lightens their load. In malignant disease of the stomach, soured milk will frequently be retained when all other foods are rejected. In cases of neurasthenia and gout it has also proved of value, and in the "run-down" condition which is so common in middle life. Chronic diarrhoea and certain forms of constipation have in numerous instances yielded to the treatment, the whey culture being usually found the most suitable. Then, in some forms of anæmia, the lactic acid cultures have proved most successful, and, as a means of rendering the gastro-intestinal track aseptic previous to operations, they have proved of considerable value.

If all this has been accomplished in a year or two, what may not we look forward to in the future when more extended use and experiment shall have more fully exhausted the possibilities of the cure? But if we follow the example of the different nations who have so long used soured milk as a regular article of diet, does it not seem probable that we may eliminate some, at least, of the causes of ill-health that call for the intervention of the doctor?

The human organism is by no means perfect; we have within us many defective parts, and some organs whose working seems to be against the welfare of the economy. It has now been clearly shown that one of the chief of these is the large intestine, as to the use of which only vague and unsatisfactory theories have been formed. There can be no doubt as to the damage which it frequently inflicts on the system, and, thanks to the researches of Professor Metchnikoff and other investigators, we seem to be in possession of a natural remedy which is sufficient to deal with the evils it produces.

FOOTNOTES:

[1] _Discoveries in Nineveh and Babylon_, by Layard, chap. xiii.

[2] Ex. xviii. and xxiii.; Lev. ii. and xi.

[3] _Encyclo. Biblica._

[4] Burckhardt and Doughty.

[5] _Annals of Dairying in Europe_, by Loudon M. Douglas.

[6] Burckhardt, _Bedouins_.

[7] This word is spelt in a great many ways by different writers: _Yoghourt_ would seem to be the one most favoured.--AUTHOR.

[8] _Damascus and Palmyra_, by Chas. G. Addison, 1838.

[9] _Travels in Syria and the Holy Land_, by Burckhardt, 1822.

[10] _Lands of the Saracens_, by B. Taylor.

[11] _Travels through Sweden, Finland, and Lapland and to the North Cape in the years 1798 and 1799_, by Joseph Acerbi, 1802.

[12] Letter to the author, from Mr. H. Cavendish Venables, British Vice-Consul at Varna.

[13] _One Hundred and Twenty Years of Life_, by Reinhardt; _The Secret of Longevity_, by an F.R.M.S.

[14] _Foods, their Composition and Analysis_, by A. W. Blyth.

[15] _Dictionary of Applied Chemistry_, by T. E. Thorpe, C.B.

[16] _Koumiss or Fermented Mares' Milk and its Uses, and the Treatment and Cure of Pulmonary Consumption and Other Diseases_, by L. Carrick, M.D., 1881.

[17] _Transactions of the Royal Society of Edinburgh_, vol. i.

[18] Clarke's _Travels_, 1810.

[19] 1845.

[20] _Dictionary of Applied Chemistry_, by Thorpe.

[21] A leathern bottle.

[22] "I have brought forward Tchembulatof's receipt, which differs from Bogoyavlensky's in the use of a larger quantity of millet-flour, and in the boiling of the latter apart from the milk. Dr. Postnikof's plan is the following: Half a pound of millet-flour and a quarter of a pound of malt are mixed with a sufficient quantity of honey to form a paste, which is put into a clean jar, covered with a linen cloth, and placed on a warm stove. The mass soon begins to rise, and is then taken out, wrapped in a piece of muslin, and dropped into a clean earthenware vessel, containing about a quart of new mares' milk, which is placed in the same temperature that the paste was kept in. As soon as signs of fermentation begin to show themselves in the fluid, the paste must be removed, while the milk, after being stirred, should be left in the same temperature till bubbles appear (only in very small quantities) on its surface. The ferment is then ready."

[23] _Food and the Principles of Dietetics._

[24] _Food and the Principles of Dietetics_, by Robert Hutchison, M.D.

[25] _Bacteria in Milk and its Products_, by Conn.

[26] _Dict. App. Chem._, Thorpe.

[27] _Nature_, July 23, 1884.

[28] _The Exploration of the Caucasus_, by Duncan W. Freshfield, 1896.

[29] Quoted by George M. Sternberg, M.D., LL.D., _Text-Book of Bacteriology_, 1898.

[30] _Encyclo. Biblica._

[31] Conn.

[32] _Cyclo. of Biblical Lit._, M'Clintock and Strong, and Burckhardt's _Arabia_.

[33] _The Indian Medical Gazette_, Sept., 1909, "A New Lactic Acid producing Streptothrix," by Gopal Ch. Chatterjee, M.B.

[34] In their studies on Leben in the _Annales de l'Institut Pasteur_ of 1899, Rist and Khoury, in speaking of the amount of lactic acid produced by _Streptobacillus lebenis_ in milk, say "Nous avons mesuré cette acidité dans une culture sur petit lait de vingt-quatre heures; elle était .261 grms. per cent. exprimée en acide lactique," which will make the amount of lactic acid produced in one litre of milk 2.61 grms. The production of this small amount of lactic acid does not tally with the ordinary view of the vigorous lactic-acid-producing power of the bacillus.

[35] _Prolongation of Life._

[36] _Prolongation of Life._

[37] An accurate census of Bulgaria is being prepared and will exhibit the cases of long life in that country.

[38] See A. Rosam, _Österreichische Molkerei Zeitung_, 15, p. 31.

[39] _Revue générale du Lait_, vii., pp. 8 and 9 (letter from Dr. Otakar Laxa of Prague, Bohemia, to the author).

[40] _On the Prolongation of Human Life_, by Élie Metchnikoff; also _The Century Magazine_, Nov., 1909, "The Utility of Lactic Microbes," by the same author.

[41] _Century Magazine_, Nov., 1909.

[42] See _Annals of Dairying in Europe_, by Loudon M. Douglas.

[43] Adapted from a report by Robert E. Turnbull, in _Live Stock Journal_.

[44] _Facts about Milk_, by R. A. Pearson, B.S., Washington.

[45] _Care and Handling of Milk_, Marshall and Wright, Bulletin 221, Michigan, 1904.

[46] _Journal of the Royal Society of Arts_, March 6, 1908--"Modern Dairy Practice," by Loudon M. Douglas.

[47] Skolotowski, _Wratsch_, 1883 (Russian), from Codwyssozki.

[48] Podowyssozki, _Zeitschr. f. diat. u. physik. Therapie_ vol. v., 1901, p. 570.

[49] Hammersten, _Jahresb. u. d. Fortsch. d. Tierchem_, 1886, Bd. 16, p. 163.

[50] Essaulow, _Dissert. Moscow_, 1895, _Abstr., Koch's Jahresb._, 1895, Bd. 6, p. 222.

[51] Kern, _Bulletin Soc. des Naturalistes de Moscow_, 1881, 3, p. 141.

[52] Krannhals, _Deutsch. Arch. f. Klin. Med._, 1884, Bd. 35, p. 18.

[53] Beijerinck, _Centralbl. Bakt. Par._, 1889, Bd. 6, p. 44.

[54] Scholl, _Die Milch_, Wiesbaden, 1891, p. 38.

[55] Adametz, _Centralbl. Bakt. Par._, 1889, Bd. 5, p. 116.

[56] Freudenreich, _Landw. Jahrb. d. Schweiz._, 1896, vol. x., p. 1.

[57] Nikolaiewa, _Annals of the Botan. Lab. of the Med. Inst. for Women_, No. 10. St. Petersburg, 1907.

[58] Kuntze, _Centralbl. Bakt. Par._, 1909, 24, p. 101.

[59] See Chap. II.

[60] Rubinsky, _Centralbl. Bakt. Par. II._, 1910, vol. xxviii., p. 161.

[61] Biel, _Jahresb. ü. d. Fortschr. d. Tierchem_, 1886, 16, p. 159.

[62] Allik, _Dissertat. Dorpat._, 1896, 19, p. 303.

[63] Fleischmann, _Lehrb. d. Milchwirtschaft_, 2d edition. Bremen, 1898.

[64] Rist and Khoury, _Annal. Pasteur_, 1902, 16, p. 65.

[65] Guerbet, _Comptes Rendus_, 1906.

[66] Weigmann, _Lafar's Handb. d. Techn. Mykol._, 2d edit., 1905, vol. ii., p. 134.

[67] Emmerling, _Cent. Bakt. Par._ 1898, vol. iv., p. 418.

[68] Lindner, _Mikroscop. Betriebscontrolle, i. d. Gärungsgew_, 3d edit., Berlin, 1901.

[69] Kalantharianz, _Dissert. Berlin_, Abs. in _Koch's Jahresb._, 1898, Bd. 9.

[70] Luerssen and Kühn, _Centralbl. Bakt._

[71] Piorkowski, _Sitzungsber. der Berl. med. Ges._, Nov., 1907.

[72] Metchnikoff, _The Prolongation of Life._

[73] Grigoroff, _Revue Médicale de la Suisse Romande_, 1905, p. 10.

[74] Grixoni, _Abstr. Cent. Bakt. Par._ 11, 15, p. 750.

[75] Freudenreich and Jensen, _Cent. Bakt. Par._ 11, 1897, 3, 545.

[76] Moro, _Wien. klin. Wochenschr._, 5, 1900.

[77] Makrinoff, _Cent. Bakt. Par._ 11, 1910, vol. xxvi., p. 374.

[78] White and Avery, _Cent. Bakt. Par._ II, 1909, vol. xxv., p. 161.

[79] Hastings and Hammer, _Research Bull., Wisconsin Experimental Station_, 6, 1909.

[80] Boutroux, _Comp. Rend._, 86, 1905, 605.

[81] Richet, _Comp. Rend._, 86, 1905, 550.

[82] Koning, _Milchw. Zentralbl._, 1905, 1, 280.

[83] Heinemann, _Centralbl. Bakt. Par._ 1908, 21, 57.

[84] Chap. I.

[85] Metchnikoff, _The Prolongation of Life_, 1908, p. 161.

INDEX

A

Acerbi, 8

Acidity of milk, 64

Adametz on keffir, 92

Albumen, 52

Alcoholic fermentation, 17, 84

Allen & Hanbury's apparatus, 132

American incubating apparatus, 149

Analysis of milk, 48, 61

Aneyza Bedouins, 2

Arabs, 2

Arakà, 106

Ash of milk, 56

B

_Bacillus acidi lactici_, 107, 112

_Bacillus acidophilus_, 110, 112

_Bacillus bulgaricus_, 39, 46, 82, 108, 110, 123, 154

_Bacillus casei_, 113

_Bacillus caucasicus_, 92, 94, 95, 119

_Bacillus caucasina_, 39

_Bacillus coli_, 45

_Bacillus esterificans_, 96

_Bacillus keffir_, 96, 97

_Bacillus lebenis_, 105

_Bacillus matzoon_, 109, 110

Bacillus of long life, 46

_Bacillus putrificus_, 122

_Bacillus subtilis_, 90, 92, 107

Bacteria in milk, 76

Bacteriology of fermented milks, 84

_Bacterium acidi lactici_, 92, 96

_Bacterium aërogenes_, 92, 96

_Bacterium coli commune_, 119, 122

_Bacterium sardous_, 110, 111

Balkan Peninsula, 4

Bedouins, 2

Beijerinck on keffir, 91

Biestings, 63

Biology of the keffir grain, 90

Blood, water contents of, 50

Bourgoul, 6

Bulgarian maya, 10, 109

Bulgaricus group, cultural characteristics of, 115

Burckhardt, 6

Butin, 51

Butyric acid fermentation, 16

Butyrin, 51

C

Camels' milk, 2

Caprinin, 51

Capronin, 51

Caprylin, 51

Carrick on koumiss, 18

Casein, 52, 53

Centenarians in Servia, Bulgaria, and Roumania, 41

Chatterjee on Dadhi, 38

Chemistry of milk, 47

Chocolate preparations and the soured-milk bacillus, 137

Citrates in milk, 57

Clay, Paget & Company's apparatus, 132

Coagulation of casein, 59

_Colitis_, 45

Colostrum, 63

Constituents of milk, 48

Continuous apparatus for producing soured milk, 81

Creamometer, 62

D

Dadhi, 15, 38

Dairy Machinery & Construction Company's apparatus, 80, 82

Dairy Outfit Company's apparatus, 145

Dairy Supply Company's apparatus, 143; steriliser, 148

Dirt in milk, 63

Diseases of keffir grains, 97

_Dispora caucasia_, 34, 90

Dried sour milk, 5

Duclaux, 51

E

Edgar's "Lactogenerator," 143

Eggs, yolk of, 52

_Enteritis_, 45

Enzymes in milk, 57

Equipment for town's dairy, 80

Essaulow on keffir, 89, 92

F

Fat of milk, 50

Ferments at the altar, 3

Flügge, 35

Freshfield on keffir, 33

Freudenreich, 92

G

Gaseous fermentation, 84

Gay-Lussac, 17

Gioddu, 107

Globulin, 54

Grieve, Dr. John, on koumiss, 19

H

Hammerstein on keffir, 89

Handling of milk, 68

Health and disease, 151

Hearson & Company's "Lactobator," 141

Hebrews, 3

Houran, inhabitants of, 6

Hueppe, 16

Hutchinson, Dr. H. B., bacillus from English market milk, 120

Hutchison on koumiss, 30

I

Ice chest, 136

Impure cultures, 158

Incubators, 141

India, 1

International Dairy Federation, 68

J

Jebours, 3

K

Kalmucks, 20

Keffir, 15, 32, 85; old, 88

Keffir grain, biology of, 90

Kephir, 34, 85. _See also_ Keffir.

Keshk, 6

Keshk-leben, 6

Koumiss, 15, 18; Bogoyavlensky's method of preparation, 28, 98; analysis, 102; artificial, 102

Krannhals on keffir, 91

Kuntze, 95

L

Lactic acid, bacillus, 16; cultures, 55; fermentation, 16, 84; Ferments apparatus, 131

"Lacto" apparatus, 145

"Lactobacilline," 158

_Lactobac. caucasicus_, 91

_Lactobacillus keffir_, 94

Lactometer, 64

Lapland, 8

Laurin, 51

Layard, 2

Leben, 15, 37, 104

Leben Raïb, 104

Lecithin, 52

"Le Ferment" apparatus, 128

Liebig, 17

Longevity, 155

M

Mares' milk, 24

Matzoon, 15, 38, 106

Maya, 42; Bulgarian, 10

Maya Bulgare Company's apparatus, 131

Meeresy, 5

Metchnikoff, 34, 40, 44, 121, 158, 163

Micro-organisms, discovery of, 13

Middle Ages, 13

Milk-filling apparatus for bottles, 82

Milk, general properties of, 57; of different animals, 60; supply of the United Kingdom, 69; industry in the United States, 71; management, 74

Mitscherlich, 17

Myristin, 51

N

Neolithic times, 1

Nikolaiewa, 95

Nitrogenous constituents of milk, 52

O

Ojràn, 106

Olein, 51

Oxygala of Pliny, 4

P

Paleolithic times, 1

Palmitin, 51

Pasteur, 14, 78

Pasteurisation, 78

Pelouze, 17

Pilaff of rice, 5

Pina, 21

Podowyssowski on keffir, 87

Preparation, of soured milk, 81; in the house, 125; in the dairy, 139

Primary cooler, 78

Proteids, 53

Pyrenees, 4

R

Reindeer's milk as soured milk, 8

Rubruquis, William de, 19

S

_Saccharomyces cerevisseæ_, 90

_Saccharomyces keffir_, 32, 33, 91, 93, 94

Sakwaska, 88

Sale of Food and Drugs Act, 1899, 49

Scheele, 17

Scholl on keffir, 91

Scythians, 18

Secondary cooler, 79

Shammar Bedouins, 2

Sheneena, 2

Skolotowski on keffir, 86

Smith, Professor Robertson, 3

Soured milk, in the house, 125; in the dairy, 139; in health and disease, 151; from impure cultures, 158; use of, 159

Souring of milk, 47, 54

Specific gravity of milk, 65

Stearin, 51

Steriliser, 148

_Streptobacilli lebeni_, 39

_Streptobacillus lebenis_, 111

_Streptococcus a_, 93, 94

_Streptococcus acidi lactici_, 95, 96

_Streptococcus b_, 93, 94

_Streptococcus lacticus_, 92, 93, 122, 124

Sugar of milk, 54

Sugar preparations and the soured-milk bacillus, 137

Suter-Naef on Swiss koumiss, 26

Swedish whey cheese, 60

Swiss hard cheese, 113

Symptoms of disease, 161

T

Temperature allowances when testing milk, tables of, 66

Town's dairy equipment, 80

Transmission of disease by milk, 72

U

United Kingdom, milk supply of, 69

United States, milk industry of, 71

Urgoutnik, 43

V

Van Leeuwenhoek, 13

Variation limits of milk, 49

Vedas, 1

"Veronelle" apparatus, 132

Vina, 21

Vinous fermentation, 17

W

Willows Refrigerating Company's apparatus, 144, 145

Wilson on koumiss, 23

Y

Yoghourt, 9, 42, 46, 107

Yoghourt bacillus, 109

Z

Zakvaska, 42

* * * * *

Putnam's Science Series

1. +The Study of Man.+ By A. C. HADDON.

2. +The Groundwork of Science.+ By ST. GEORGE MIVART.

3. +Rivers of North America.+ By ISRAEL C. RUSSELL.

4. +Earth Sculpture, or; The Origin of Land Forms.+ By JAMES GEIKIE.

5. +Volcanoes; Their Structure and Significance.+ By T. G. BONNEY.

6. +Bacteria.+ By GEORGE NEWMAN.

7. +A Book of Whales.+ By F. E. BEDDARD.

8. +Comparative Physiology of the Brain, etc.+ By JACQUES LOEB.

9. +The Stars.+ By SIMON NEWCOMB.

10. +The Basis of Social Relations.+ By DANIEL G. BRINTON.

11. +Experiments on Animals.+ By STEPHEN PAGET.

12. +Infection and Immunity.+ By GEORGE M. STERNBERG.

13. +Fatigue.+ By A. MOSSO.

14. +Earthquakes.+ By CLARENCE E. DUTTON.

15. +The Nature of Man.+ By ÉLIE METCHNIKOFF.

16. +Nervous and Mental Hygiene in Health and Disease.+ By AUGUST FOREL.

17. +The Prolongation of Life.+ By ÉLIE METCHNIKOFF.

18. +The Solar System.+ By CHARLES LANE POOR.

19. +Heredity.+ By J. ARTHUR THOMPSON, M.A.

20. +Climate.+ By ROBERT DECOURCY WARD.

21. +Age, Growth, and Death.+ By CHARLES S. MINOT.

22. +The Interpretation of Nature.+ By C. LLOYD MORGAN.

23. +Mosquito Life.+ By EVELYN GROESBEECK MITCHELL.

24. +Thinking, Feeling, Doing.+ By E. W. SCRIPTURE.

25. +The World's Gold.+ By L. DE LAUNAY.

26. +The Interpretation of Radium.+ By F. SODDY.

27. +Criminal Man.+ By CESARE LOMBROSO.

28. +The Origin of Life.+ By H. CHARLTON BASTIAN.

29. +The Bacillus of Long Life.+ By LOUDON M. DOUGLAS.

_For list of works in preparation see end of this volume_

* * * * *

_A Selection from the Catalogue of_

G. P. PUTNAM'S SONS

Complete Catalogue sent on application

Putnam's Science Series

+1.--The Study of Man.+ By Professor A. C. HADDON, M.A., D.Sc., M.R.I.A. Fully illustrated. 8°, net $2.00.

"A timely and useful volume.... The author wields a pleasing pen and knows how to make the subject attractive.... The work is calculated to spread among its readers an attraction to the science of anthropology. The author's observations are exceedingly genuine and his descriptions are vivid."--_London Athenæum._

+2.--The Groundwork of Science.+ A Study of Epistemology. By ST. GEORGE MIVART, F.R.S. 8°, net $1.75.

"The book is cleverly written and is one of the best works of its kind ever put before the public. It will be interesting to all readers, and especially to those interested in the study of science."--_New Haven Leader._

+3.--Rivers of North America.+ A Reading Lesson for Students of Geography and Geology. By ISRAEL C. RUSSELL, Professor of Geology, University of Michigan, author of "Lakes of North America," "Glaciers of North America," "Volcanoes of North America," etc. Fully illustrated. 8°, net $2.00.

"There has not been in the last few years until the present book any authoritative, broad résumé on the subject, modified and deepened as it has been by modern research and reflection, which is couched in language suitable for the multitude.... The text is as entertaining as it is instructive."--_Boston Transcript._

+4.--Earth Sculpture; or, The Origin of Land-Forms.+ By JAMES GEIKIE, LL.D., D.C.L., F.R.S., etc., Murchison Professor of Geology and Mineralogy in the University of Edinburgh; author of "The Great Ice Age," etc. Fully illustrated. 8°, net $2.00.

"This volume is the best popular and yet scientific treatment we know of the origin and development of land-forms, and we immediately adopted it as the best available text-book for a college course in physiography.... The book is full of life and vigor, and shows the sympathetic touch of a man deeply in love with nature."--_Science._

+5.--Volcanoes.+ By T. G. BONNEY, F.R.S., University College, London. Fully illustrated. 8°, net $2.00.

"It is not only a fine piece of work from a scientific point of view, but it is uncommonly attractive to the general reader, and is likely to have a larger sale than most books of its class."--_Springfield Republican._

+6.--Bacteria+: Especially as they are related to the economy of nature, to industrial processes, and to the public health. By GEORGE NEWMAN, M.D., F.R.S. (Edin.), D.P.H. (Camb.), etc., Demonstrator of Bacteriology in King's College, London. With 24 micro-photographs of actual organisms and over 70 other illustrations. 8°, net $2.00.

"Dr. Newman's discussions of bacteria and disease, of immunity, of antitoxins, and of methods of disinfection, are illuminating, and are to be commended to all seeking information on these points. Any discussion of bacteria will seem technical to the uninitiated, but all such will find in this book popular treatment and scientific accuracy happily combined."--_The Dial._

+7.--A Book of Whales.+ By F. E. BEDDARD, M.A., F.R.S. Illustrated 8°. $2.00.

"Mr. Beddard has done well to devote a whole volume to whales. They are worthy of the biographer who has now well grouped and described these creatures. The general reader will not find the volume too technical, nor has the author failed in his attempt to produce a book that shall be acceptable to the zoologist and the naturalist."--_N. Y. Times._

+8.--Comparative Physiology of the Brain and Comparative Psychology.+ With special reference to the Invertebrates. By JACQUES LOEB, M.D., Professor of Physiology in the University of Chicago. Illustrated. 8°. $1.75.

"No student of this most interesting phase of the problems of life can afford to remain in ignorance of the wide range of facts and the suggestive series of interpretations which Professor Loeb has brought together in this volume."--JOSEPH JASTROW, in the _Chicago Dial._

+9.--The Stars.+ By Professor SIMON NEWCOMB, U.S.N., Nautical Almanac Office, and Johns Hopkins University. 8°. Illustrated. Net. $2.00. (By mail, $2.00.)

"The work is a thoroughly scientific treatise on stars. The name of the author is sufficient guarantee of scholarly and accurate work."--_Scientific American._

+10.--The Basis of Social Relations.+ A Study in Ethnic Psychology. By DANIEL G. BRINTON, A.M., M.D., LL.D., Sc.D., Late Professor of American Archæology and Linguistics in the University of Pennsylvania; Author of "History of Primitive Religions," "Races and Peoples," "The American Race," etc. Edited by LIVINGSTON FARRAND, Columbia University. 8°. Net, $1.50 (By mail, $1.60.)

"Professor Brinton has shown in this volume an intimate and appreciative knowledge of all the important anthropological theories. No one seems to have been better acquainted with the very great body of facts represented by these sciences."--_Am. Journal of Sociology._

+11.--Experiments on Animals.+ By STEPHEN PAGET. With an Introduction by Lord Lister. Illustrated. 8°. Net, $2.00. (By mail, $2.20.)

"To a large class of readers this presentation will be attractive, since it gives to them in a nut-shell the meat of a hundred scientific dissertations in current periodical literature. The volume has the authoritative sanction of Lord Lister."--_Boston Transcript._

+12.--Infection and Immunity.+ With Special Reference to the Prevention of Infectious Diseases. By GEORGE M. STERNBERG, M.D., LL.D., Surgeon-General U. S. Army (Retired). Illustrated. 8°. Net, $1.75 (By mail, $1.90.)

"A distinct public service by an eminent authority. This admirable little work should be a part of the prescribed reading of the head of every institution in which children or youths are gathered. Conspicuously useful."--_N. Y. Times._

+13.--Fatigue.+ By A. MOSSO, Professor of Physiology in the University of Turin. Translated by MARGARET DRUMMOND, M.A., and W. B. DRUMMOND, M.B., C.M., F.R.C.P.E., extra Physician, Royal Hospital for Sick Children, Edinburgh; Author of "The Child. His Nature and Nurture." Illustrated. 8°. Net, $1.50.

"A book for the student and for the instructor, full of interest, also for the intelligent general reader. The subject constitutes one of the most fascinating chapters in the history of medical science and of philosophical research."--_Yorkshire Post._

+14.--Earthquakes.+ In the Light of the New Seismology By CLARENCE E. DUTTON, Major, U. S. A. Illustrated 8°. Net, $2.00. (By mail, $2.20.)

"The book summarizes the results of the men who have accomplished the great things in their pursuit of seismological knowledge. It is abundantly illustrated and it fills a place unique in the literature of modern science"--_Chicago Tribune._

+15.--The Nature of Man.+ Studies in Optimistic Philosophy. By ÉLIE METCHNIKOFF, Professor at the Pasteur Institute. Translation and introduction by P. CHAMBERS MITCHELL, M.A., D.Sc. Oxon. Illustrated. 8°. Net, $1.50.

"A book to be set side by side with Huxley's Essays, whose spirit it carries a step further on the long road towards its goal"--_Mail and Express._

+16.--The Hygiene of Nerves and Mind in Health and Disease.+ By AUGUST FOREL, M.D., formerly Professor of Psychiatry in the University of Zurich. Authorized Translation. 8°. Net, $2.00. (By mail, $2.20.)

A comprehensive and concise summary of the results of science in its chosen field. Its authorship is a guarantee that the statements made are authoritative as far as the statement of an individual can be so regarded.

+17.--The Prolongation of Life.+ Optimistic Essays. By ÉLIE METCHNIKOFF, Sub-Director of the Pasteur Institute. Author of "The Nature of Man." etc. 8°, Illustrated Net, $2.50. (By mail, $2.70.) Popular Edition. With an introduction by Prof. CHARLES S. MINOT. Net, $1.75.

In his new work Professor Metchnikoff expounds at greater length, in the light of additional knowledge gained in the last few years, his main thesis that human life is not only unnaturally short but unnaturally burdened with physical and mental disabilities. He analyzes the causes of these disharmonies and explains his reasons for hoping that they may be counteracted by a rational hygiene.

+18.--The Solar System.+ A Study of Recent Observations. By Prof. CHARLES LANE POOR, Professor of Astronomy in Columbia University. 8°. Illustrated. Net, $2.00.

The subject is presented in untechnical language and without the use of mathematics. Professor Poor shows by what steps the precise knowledge of to day has been reached and explains the marvellous results of modern methods and modern observations.

+19.--Climate--Considered Especially in Relation to Man.+ By ROBERT DECOURCY WARD, Assistant Professor of Climatology in Harvard University. 8°. Illustrated. Net, $2.00.

This volume is intended for persons who have not had special training in the technicalities of climatology. Climate covers a wholly different field from that included in the meteorological text-books It handles broad questions of climate in a way which has not been attempted in a single volume The needs of the teacher and student have been kept constantly in mind.

+20.--Heredity.+ By J. ARTHUR THOMSON, M.A., Professor of Natural History in the University of Aberdeen; Author of "The Science of Life," etc. 8°. Illustrated. Net, $3.50.

The aim of this work is to expound, in a simple manner, the facts of heredity and inheritance as at present known, the general conclusions which have been securely established, and the more important theories which have been formulated.

+21.--Age, Growth, and Death.+ By CHARLES S. MINOT, James Stillman Professor of Comparative Anatomy in Harvard University, President of the Boston Society of Natural History, and Author of "Human Embryology," "A Laboratory Text-book of Embryology," etc. 8°. Illustrated.

This volume deals with some of the fundamental problems of biology, and presents series of views (the results of nearly thirty years of study), which the author has correlated for the first time in systematic form.

+22.--The Interpretation of Nature.+ By C. LLOYD MORGAN, LL.D., F.R.S. Crown 8vo. Net, $1.25.

Dr Morgan seeks to prove that a belief in purpose as the causal reality of which nature is an expression is not inconsistent with a full and whole-hearted acceptance of the explanations of naturalism.

+23.--Mosquito Life.+ The Habits and Life Cycles of the Known Mosquitoes of the United States; Methods for their Control; and Keys for Easy Identification of the Species in their Various Stages. An account based on the investigation of the late James William Dupree, Surgeon-General of Louisiana, and upon the original observations by the Writer. By EVELYN GROESBEECK MITCHELL, A.B., M.S. With 64 Illustrations. Crown 8vo. Net, $2.00.

This volume has been designed to meet the demand of the constantly increasing number of students for a work presenting in compact form the essential facts so far made known by scientific investigation in regard to the different phases of this, as is now conceded, important and highly interesting subject. While aiming to keep within reasonable bounds, that it may be used for work in the field and in the laboratory, no portion of the work has been slighted, or fundamental information omitted, in the endeavor to carry this plan into effect.

+24.--Thinking, Feeling, Doing.+ An Introduction to Mental Science. By E. W. SCRIPTURE, Ph.D., M.D., Assistant Neurologist Columbia University, formerly Director of the Psychological Laboratory at Yale University. 189 Illustrations. 2d Edition, Revised and Enlarged. Crown 8vo. Net, $1.75.

"The chapters on Time and Action, Reaction Time, Thinking Time, Rhythmic Action, and Power and Will are most interesting. This book should be carefully read by every one who desires to be familiar with the advances made in the study of the mind, which advances, in the last twenty-five years, have been quite as striking and epoch-making as the strides made in the more material lines of knowledge."--_Jour. Amer. Med. Ass'n._, Feb. 22, 1908.

+25.--The World's Gold.+ By L. DE LAUNAY, Professor at the École Superieure des Mines. Translated by Orlando Cyprian Williams. With an Introduction by Charles A. Conant, author of "History of Modern Banks of Issue," etc. Crown 8vo. Net, $1.75.

M. de Launay is a professor of considerable repute not only in France, but among scientists throughout the world. In this work he traces the various uses and phases of gold; first, its geology; secondly, its extraction; thirdly, its economic value.

+26.--The Interpretation of Radium.+ By FREDERICK SODDY, Lecturer in Physical Chemistry in the University of Glasgow. Crown 8vo. With Diagrams. Net, $1.75.

As the application of the present day interpretation of Radium (that it is an element undergoing spontaneous disintegration) is not confined to the physical sciences, but has a wide and general bearing upon our whole outlook on Nature, Mr. Soddy has presented the subject in non-technical language, so that the ideas involved are within reach of the lay reader. No effort has been spared to get to the root of the matter and to secure accuracy, so that the book should prove serviceable to other fields of science and investigation, as well as to the general public.

+27.--Criminal Man.+ According to the Classification of CESARE LOMBROSO. Briefly Summarized by his Daughter, Gina Lombroso Ferrero. With 36 Illustrations and a Bibliography of Lombroso's Publications on the Subject. Crown 8vo. Net, $2.00.

Signora Guglielmo Ferrero's résumé of her father's work on criminal anthropology is specially dedicated to all those whose office it is to correct, reform, and punish the criminal, with a view to diminishing the injury caused to society by his anti-social acts; also to superintendents, teachers, and those engaged in rescuing orphans and children of vicious habits, as a guide in checking the development of evil germs and eliminating incorrigible subjects whose example is a source of corruption to others.

* * * * *

The most valuable production since Darwin's "Origin of Species."

The Nature of Man

_Studies in Optimistic Philosophy_

By Élie Metchnikoff

Sub-Director of the Pasteur Institute, Paris

Translated with an Introduction by

P. Chambers Mitchell

Secretary of the Zoölogical Society

Octavo. Illustrated. Popular Edition. $1.50 net. By mail, $1.65

It is not often that a scientific book may be read with ease, profit, and pleasure by the general reader, so that M. Metchnikoff's book comes in the nature of an agreeable surprise. It is marked by a refreshing _naïveté_ and a large simplicity which are characteristically Russian. The scientific importance of this work is so great that it is spoken of in England as the most valuable production since Darwin's _Origin of Species_.

Opinions of the Press

"An extremely interesting and typical book.... With a distinguished frankness, M. Metchnikoff defines his attitude to our universal prepossessions. It is his theory that the infirmities of age are to be overcome. If there be ground for this conception, humanity is to be profoundly changed and what we call life now, will be the childhood and youth of that longer and larger life."--H. G. WELLS, in _London Speaker_.

"Undoubtedly a great book (in some quarters it has been hailed as the greatest since Darwin's famous message to the world) and should be read by all intelligent men and women."--_The Nation._

"A book to be set side by side with Huxley's Essays, whose spirit it carries a step further on the long road towards its goal."--_Mail and Express._

New York--G. P. Putnam's Sons--London

* * * * *

"_Remarkable for its simple language and clear style.... Bears the stamp of a production of an erudite scientist and a deep thinker._"--Science.

The Prolongation of Life

Optimistic Essays

_By_ Élie Metchnikoff

_Author of "The Nature of Man," etc._

_8vo. Illustrated Popular Edition. $1.75 net By mail, $1.90_

M. Élie Metchnikoff is one of those rare scientists who have found a way to lay hold of and present to the world in untechnical phraseology, intelligible to the lay mind, such results of his researches as are of universal interest and go straight home to the bosoms and business of intelligent men. _The Nature of Man_, by the same author, was one of the most fascinating books, at once popular, and scientific, which have appeared for decades. The book here in question will stand beside it as a worthy companion volume. It is satisfactory to report that, absorbed as Metchnikoff is in "material" problems, and deep as he is in the mysteries of the physical universe, these essays show him to be an optimist who speaks with no uncertain voice.

A great deal of attention is given in _The Prolongation of Human Life_ to the subject of old age and its causes, with scientific observations of special cases among human beings and the lower animals. The author suggests means of prolonging life and health, while contemplating natural death with serenity, and finding that agreeable sensations accompany its approach. Beyond a certain point it seems to him a disadvantage to prolong life. Passing on from these mortuary lucubrations, the essays concern themselves with psychological matters, with optimism and pessimism and in general with questions of science and morals. The temperaments of certain great men are analyzed in studies that have for their subjects respectively Byron, Leopardi, Schopenhauer, and Goethe. In the preface the author says that he has avoided, as far as possible, repeating points which have been sufficiently treated in _The Nature of Man_.

G. P. PUTNAM'S SONS

NEW YORK LONDON

End of Project Gutenberg's The Bacillus of Long Life, by Loudon Douglas