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Bitter has found that milk in sterilized and unsterilized cans varies greatly in keeping properties after Pasteurization.

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But that temperature is the main factor, has similarly been shown by Bitter in his experiments with Pasteurized milk. Thus when heated to 68 degrees C. and thereafter chilled, the following results were obtained:

At 30° C. milk remained good 6-8 hrs. longer than un-Pasteurized milk.

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Bitter has determined after numerous experiments to make an arbitrary standard of goodness of milk by counting the number of bacteria in the sample. Milk, according to this scale, is good if the number of bacteria falls under 50,000 per C. C. Above this it becomes doubtfully good, and when 2,000,000 per c. c. are present it is absolutely destroyed. He concludes that, with regard to the preservation of milk, Pasteurization at 68 to 75 degrees C. is safe at ordinary temperatures; that in hot summer weather it will keep at least thirty hours longer; and that at this temperature the taste and flavor are not altered and cream production is not affected.

Manifestly, however, with ordinary methods, as we find them, in the care of milk, temperature, of all factors, has the most important bearing on the keeping of milk. I cannot do better than conclude these studies with a quotation from a recent critique, by M. Duclaux, "Sur la stérilisation du lait." He says:

"It seems to me that in place of always marching forward in this direction, it would be useful to retrace our steps, and ask ourselves if it would not serve better if we should avoid all necessity for heating, in preventing absolutely the introduction of all hurtful germs into the milk. In the conference, held on the 7th of June, 1889, in the Trocadéro, during the Universal Exposition, I said, 'that milk, properly taken, in a stable properly kept, by a milker who had first washed his hands and the teats of the cow, would not coagulate more quickly than milk taken without care, and having carbonate of soda added to it to mask the defects of cleanliness.' * • It seems to me that in this direction lies progress, at least for milks destined for rapid consumption, and not from the side of the multiplication, or making perfect, of apparatus for Pasteurization.""

*

Summing up, then, some of the practical conclusions to be derived from our studies, I would briefly formulate the following, as methods likely to conduce to an improvement in our public milk supplies.

1. After intelligent dairymen have selected their cows, it is especially desirable that a system of periodic veterinary inspection, in addition to the dairymen's inspection, be exercised, under the municipal health department, of all milch cows supplying milk to the municipality.

2. From what has already been said it is manifest that strong views should be held and taught regarding the nature and quality of the food of milch cows, whose milk is intended for public supplies. Not only has it a direct influence on the general health of the cow, but the condition of the milk at the time of taking, and also its keeping qualities, are undoubtedly in no small degree dependent on the character of the food supply. All decomposed foods, as those which are liable to undergo fermentation, should be wholly avoided. As already mentioned, the best foods are the well ripened grains and grasses, well cured and, free from weeds, fed in such a manner as to supply the various milk constituents in proper amounts, and in such a way as to promote easy digestion and proper assimilation.

3. The stables of the cows are manifestly a point of great importance. Too often, dark, damp, ill-ventilated, and crowded pens have been the home of this chief of our food supplies. It is quite possible, as hundreds of dairymen and farmers have shown on this continent as on the old, to keep, even on a large scale, a dairy stable free from the ordinary disagreeable stable odors, to give the cows abundant ventilation, and to so conduct the feeding, that cows, taken from the ordinary barn-yard feeding of the farmers, will readily improve in general appearance, and increase greatly in milk and in flesh. The water supply to the cows is of equal importance. Too often, the barn-yard pool, or sewage-tainted creek, or cheesefactory drainage, are the sources from which the dairy cattle drink; and not even to mention the more delicate physiological effects of such water, cheese makers tell us that they can distinctly note the gross effects of cows drinking filthy waters by the degraded quality of the milk which, at times, comes to their factories.

4. The care of the milk at the time of, and subsequent to, taking, is, however, of all points at once the most difficult of control and the most necessary to supplying a wholesome milk. We have pointed out wherein the difficulties lie, and would only say, as Duclaux has said, "Cleanliness everywhere is the sine qua non.” That it means almost a revolution amongst farmers and dairymen, as regards their methods, is apparent; but as Duclaux neatly says, "Producers will quickly find the means (of cleanliness and a reform in their methods) if consumers wish strongly. When people demand clean milk, they will have it. They will always have to boil milk before using, when they are not sure of the condition of the cow that furnished it; but the question will not the less have taken a great step in advance when milkmen and milkmaids know all that is implied in cleanliness." Hence, the sterilizing of the cow's teats by washing, the sterilizing of all cans and bottles by steam or dry heat, and the boiling of all cloth strainers will be necessary. Aeration and rapid cooling are of enormous influence in delaying, as we have seen,

the multiplication of bacteria, and I am convinced that the placing of milk in a refrigerator over night, at 40-45 degrees F., and allowing the cream to rise in well stoppered bottles, conduce together to the greatly increased permanency of the

normal milk condition.

5. The delivery of the milk is similarly of prime importance. If placed to cool in sterilized bottles, at a low temperature, the layer of cream tends to prevent agitation in the bottles, and where the bottles are packed at the same time in accurately fitting compartment boxes, these exactly fitting into wagons specially designed for them, the agitation or disturbance of the milk in transit will be reduced to a minimum, and the introduction of oxygen is lessened. The numerous details in this regard need not be further referred to here.

6. Finally, when the milk has reached the consumer, it must be placed in a refrigerator, or promptly consumed. If in the former, I have known milk in summer weather to retain its sweetness for three or four days when precautions such as I have spoken of are present.

7. In case the Pasteurization of milk is introduced into practice by dairymen, it is necessary that the same care should be exercised in keeping milk cool, after heating to 68 or 70 degrees F., as is necessary under ordinary treatment.

In conclusion, I may say that it is my opinion, after very carefully studying the processes and results of a large dairy for four years, that, with carefully selected and inspected cows, as regards freedom from disease, notably tuberculosis, the taking of milk with care as to cleanliness in the particulars already given, to aerating the milk to remove the volatile animal gases, to bottling in sterilized and well stoppered bottles, and the placing them promptly thereafter in cold storage, at 40 – 45 degrees F., with careful handling in delivery, will be found to present so many practical advantages, both as regards the tastes of the consumer and the convenience of the dairyman, that sterilization in other respects will not be likely to be found necessary, or find general adoption.

WATER SUPPLY AND PUBLIC HEALTH.*

BY ALLEN HAZEN, LAWRENCE, MASS.

During the last few years, there has been accumulating an overwhelming amount of evidence that typhoid fever is often transmitted from one person to another by drinking-water. I need not refer to the experience of foreign cities, but only to mention epidemics, during the past year alone, at Albany, Wheeling, Duluth, Lowell, and Lawrence, besides many others of less extent. In a part of these cases, at least, most thorough investigations have been made, showing beyond question that the excessive death-rates were due to the pollution of the public water supplies.

Investigations have also been made, both in England and in India, showing that Asiatic cholera is most frequently conveyed by drinking-water, and we have to consider what part our water supplies might take in its propagation in the unfortunate event of its gaining a foot-hold on our shores.

It behooves us, then, to give this subject most careful consideration, with a view to understanding the exact method of transmission, and, if possible, to find measures which will secure relief.

Both typhoid fever and cholera are caused by the growth within the body of particular species of bacteria, which are most frequently taken into the system through the mouth, either with the food or drink, and it is the presence of these particular germs in a water which gives it its power of causing disease. A water may be muddy, or hard, or discolored by organic matter, it may even be sewage-polluted and

*Read at the nineteenth annual meeting of the American Public Health Association.

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