Loudon M. Douglas

“ A pure milk supply is essential to health, and it seems unfortunate that the ordinary milk producer should, in a great many cases, take up an antagonistic attitude to the scientific methods of handling milk. There is a body of opinion being created, however, which is likely to alter this attitude in the next generation, and this is attributable to the fact that so much excellent work has been done at numerous dairy colleges and institutes in all civilised countries that the dairy industry is emerging from a period of rule-of-thumb procedure to its proper place as one of the technical arts. ”

“ The sugar of milk is not found anywhere else. It is a carbohydrate like cane and grape sugar—that is to say, the hydrogen and oxygen they contain are in the same relative proportions as in water. Milk sugar is not so soluble or so sweet as the other sugars. It does not ferment with ordinary yeast, but certain special yeasts which are made use of in the preparation of keffir, koumiss, etc., have the power of transforming it into alcohol. Its most remarkable property, however, is the facility with which, under the influence of certain bacteria, it is changed into lactic acid. ”

“ In the nutrition of both plants and animals large quantities of water are needed. The solids must be supplied in solution or dissolved in the assimilative processes, and this cannot take place without water, which also conveys the dissolved solids to the various parts of the economy, and in the case of animals removes waste materials. For the most part, water passes through the body unchanged, but a certain proportion unites chemically with the food materials and assists in their digestion. It is therefore not surprising that seven eighths of milk is composed of water. ”

“ But if we follow the example of the 163 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. ”

“ Since that time, the progress in dairying has been continuous, and, during recent years, attention has been directed to soured milk to such an extent that it has become necessary for all who are interested in the handling of milk and milk products to have a knowledge of the subject, as it seems clearly demonstrated that, under proper direction, there is every possibility of its forming an important element in the prolongation of life. ”

“ In the first place, milk immediately after extraction from the cow contains only a few organisms, but these multiply so rapidly that in a few hours the bacterial content may amount to many millions per ounce. In preparing a pure culture of any specific organism, then, care must be taken to destroy all the bacteria that have accidentally found their way into the milk, inoculating with the organisms it is desired to cultivate. This is best accomplished by heating the milk to the boiling-point of water for about thirty minutes, by which time almost all the undesirable bacteria have been killed. ”

“ In the eastern part of Europe, milk has always been looked upon as one of the principal kinds of food, but not necessarily the milk of cows, as, from ancient times to the present day, the milk from 2 camels, buffaloes, sheep, and goats has been used indiscriminately throughout the East.
According to Layard,1 "the Bedouins do not make cheese. The milk of their sheep and goats is shaken into butter or turned into curds; it is rarely or never drunk fresh, new milk being thought very unwholesome, as soon by experience I found it to be, in the desert. ”

“ Every one is familiar with the souring of milk, but perhaps it is not so generally known that there are great differences in the results obtained in accordance with the conditions under which the souring takes place. The skilled butter-maker, by keeping the milk in a cool and cleanly dairy, obtains a sour milk of a characteristic and agreeable aroma and taste, which beneficially affect the flavour of the butter produced. ”

“ There is no great difficulty in making soured milk at home: the necessary operations are quite simple, but at the same time they must be conducted with precision and care, otherwise the results may be unsatisfactory and disagreeable; there may even sometimes be danger in badly prepared sour milk. It is always an advantage in such matters to understand the reason of things, and a few notes on the surrounding conditions, and what has to be accomplished, may be of assistance to the would-be experimenter. ”

“ Milk is a splendid food for bacteria, and numerous varieties multiply in it exceedingly, and many of these are injurious, producing putrefactive changes which render the milk unwholesome, even poisonous in some cases. Others are beneficial, and are absolutely necessary for the souring of milk for making butter or cheese and for the ripening of the latter. The soured milk which is the subject of this book is the work of certain lactic-acid-producing bacteria, and the problem we have before us is to encourage the growth of the latter to the uttermost and to exclude the others. ”

“ 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 ”

“ The acidity of milk is a very useful guide to its age. Milk has the curious property of being "amphoteric," i.e., it is both slightly acid and slightly alkaline when fresh. As its age increases, however, so does its acidity, and at a rate varying with the temperature and moisture contents of the atmosphere in which it is placed. Old and acid milk is heavily contaminated with bacteria, a proportion of which are likely to be injurious to health. ”

“ It would seem, indeed, as if the habit of living long was well known in ancient times, and that, like many other of the valuable arts and sciences, it fell under a cloud during the Middle Ages, or, perhaps, the significance of the use of soured milk fell into neglect, and, even after the revival of letters in the sixteenth century, still remained obscure. ”

“ The remarkable property possessed by rennet, of curdling or coagulating casein, is well known; rennet is an extract from the stomach of the calf, and similar principles are present in the stomachs of man and other animals, so that the coagulation of milk is the first process in its digestion. If milk is gulped down in large quantities it is apt to coagulate in lumps, and digestion is much interfered with, but if it is taken hot and slowly, it coagulates in small pieces which are readily attacked by the gastric juice, and milk is then one of the most assimilable of foods. ”

“ Certainly, sugar is a medium in which the lactifying germs can live, but the quantity so introduced into the system must be very small compared with what is obtained from properly fermented milk. It takes some time, even with strong cultures, to fix the acid-producing germs in the large bowel where they are wanted, and until proper evidence is forthcoming that confectionery preparations are efficacious we would recommend that only the regularly fermented milk be used. ”

“ 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. ”

“ 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 156 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 various forms of sour milk which have been described in the foregoing pages may be said to be of the traditional kind, and with the light of modern knowledge, it has been possible to determine exactly what constitutes the active principle in use in the milk consumed in these countries, and, as we shall see, this principle has been applied so that, at the present day, a pure fermented milk may be obtained in any country, and there is every reason to believe that should such be adopted as a general article of food, it would contribute to the prolongation of human existence. ”

“ The majority of intelligent people are now acquainted with the fact that the germs of bacteria are to be found everywhere on the surface of the earth, in air, and in water, and that they are the sole cause of the decay of all manner of perishable articles. ”

“ 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 ”

“ Historically it may be gleaned from the fragmentary references which we have given, that soured milk has, from time immemorial, formed 12 the principal article of diet of a great many peoples, and the notable feature in connection with it is, that in some countries where it is in daily use, the age limit for human beings seems to be very much extended, and it would appear that there is a direct connection between the use of soured milk and longevity. ”

“ The dairyman who knows his business does not need to be told of the care which is necessary to keep milk in good condition. The merely commercial consideration of avoiding loss has made him ready to inquire into the best means of prolonging 141 the life of milk as a merchantable article. For a time he relied on chemical preservatives, but their day is now almost over, and filtration, pasteurisation, and cold storage have taken their place. ”

“ Milk fat or butter is more digestible than almost any other fat, and its importance therefore can readily be realised. All the above constituents of milk fat are composed of different proportions of carbon, hydrogen, and oxygen, but milk also contains minute quantities of lecithin, a fat containing phosphorus in addition. Lecithin is also found in the brain and nerve material of animals, in the yolk of egg, and in several plants.
The nitrogenous constituents of milk—casein and albumen—are usually estimated together, and they are reckoned as of equivalent food value. ”