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cause the disease seldom affects adults, who for the most part are engaged in procuring and handling milk supplies.

Tuberculosis. This disease is common in both man and cattle, and without doubt is the most serious illness affecting the human race. The presence of tuberculosis in man, in a certain proportion of cases, can now be definitely traced to the disease in cows, the connection being established through the use of infected milk.

The tuberculosis of cattle is more communicable in dairy herds than is tuberculosis in man. So frequent is the infection among dairy cattle that it is not unusual to find that as high as 10 per cent of market milk in some cities contains live tubercle bacilli. Bacilli may also exist for several months in butter, cheese, and cream in even greater number than in milk, so that such products, if infected, must be considered a source of danger. These organisms are necessarily derived solely from tuberculous cows, bacilli from human sources being relativey rare in milk. The germs either are given off in the milk itself or, what is believed to be more common, are contained in the feces and gain entrance to the milk during the process of milking. Unfortunately it is not always possible even for the most experienced person to detect by visual or physical examination cows which are suffering from tuberculosis, as the animals may present every appearance of health, hence it has been necessary to devise tests for this purpose. The test so used is known as the tuberculin test. The sole object of the tuberculin test is to determine what members of the dairy herd are infected with tuberculosis in order that such animals may be eliminated and their milk not offered for human consumption. Milk obtained from tuberculin-tested cattle is therefore to be considered safer than supplies otherwise produced.

While there are essential differences between human tubercle bacilli and those derived from cows, both must be regarded as dangerous to man. It is now considered that bovine bacilli, as found in milk, are only rarely a cause of tuberculosis of the lungs in adult man, the form commonly met with, although a proportion of cases of tuberculosis of organs other than the lungs is caused by this type of germ. On the other hand this same organism is known to be responsible for many cases of tuberculosis in children and some authorities estimate that at least 10 per cent of all tuberculous children owe their infection to this form of germ. From studies made it has also been learned that probably fully half of the cases of socalled surgical tuberculosis affecting children are due to this cause. When these expressions are translated into everyday terms the gravity of the situation becomes more apparent. Many of the pale, anemic, and weakened children seen about the streets owe their

debility not alone to close confinement and lack of proper nourishment but to polluted milk. A large percentage of the maimed and crippled can attribute their deformity to bone tuberculosis and fully one-half of these little ones have derived their trouble from the milk of tuberculous cows. The cause of enlarged glands which often require removal in boys and girls, is frequently infected milk and nothing else. All of these are important and at times serious conditions, and it is somewhat startling to learn that they can be definitely traced to the consumption of a liquid which many of us have believed to be at all times entirely harmless.

Diphtheria. This infection is of a different type from typhoid fever, the active agent or germ being present only in the nasal and mouth secretions of those afflicted. In the same way that we have healthy carriers of typhoid we also have healthy carriers of diphtheria, who constitute a frequent source of danger. Milk acts as a vehicle of infection in this disease but rarely, and only a small percentage of the total number of cases which develop can be attributed to this cause. However, the possibility of the development of the disease in this way must be borne in mind.

Septic sore throat.-This condition usually manifests itself as a tonsillitis or other form of throat inffammation and is often attended with complications which are dangerous and even at times fatal. Outbreaks are explosive in character, sometimes affecting as high as 40 per cent of the users of a particular milk supply. As in other milk-borne epidemics, children are more often attacked than adults. In nearly all cases the epidemic can be traced to the dairy and even to the particular cows responsible for the contagion. When the use of milk from this source is forbidden the epidemic ceases. The infectious agent is known to be an organism which grows in chains and this germ can be recovered from both the inflamed udders of diseased cows and from the throats of those who are made ill. Whether the infection is originally derived from man or has its source only in diseased animals is still unsettled. Even the most careful supervision of dairies may be of little avail in protecting the public against this disease.

Foot-and-mouth disease.-This is a highly communicable disease of cattle which very rarely affects man. The condition is of such serious economic importance to live-stock interests, however, that the most rigid quarantine measures are practiced for its suppression, and this is probably the chief reason for its infrequency in human beings. Man contracts the disease from infected cows either by actual contact or from the consumption of raw milk or any of its products, such as ice cream, butter, or even cheese. The illness in man is not of a serious nature and often goes unrecognized.

Diarrhea and enteritis.-Doubtless quite the most frequent disease brought about by impure milk is diarrhea and enteritis, a common affection of infancy which annually accounts for over 65,000 deaths in the United States of children under the age of 2 years. It is true that milk can not be held entirely responsible for this frightful mortality, such conditions as overcrowding, filth, heat, and ignorance being predisposing and contributing factors, but impure milk is frequently the exciting cause, a fact which is now perfectly well established. In those cities which have carefully guarded milk supplies the infant mortality rate is generally low. It is entirely feasible for any city to protect in a measure the lives of its babies by simple. regulation of the milk supply. Logically, what is true for the community is likewise true proportionately at least for the home.

The mortality among infants fed on cow's milk is ten times as great as among those nursing from their own mothers; the cause of this is not entirely the difference in the proportion of the natural ingredients of the milk, but is due in part to bacteria and filth which gain entrance thereto. It is very likely that "summer diarrhea" is in the majority of instances caused by a distinct germ, and that the conveyor of the infection is usually cow's milk, the organism gaining access to the supply in much the same manner as the typhoid bacillus. Diarrhea and enteritis in both infants and adults may likewise be brought about by abnormal conditions of the cows themselves. Milk from animals suffering from inflammation of the digestive tract often produces symptoms in the consumer and should not be used. Inflammatory conditions of the udder are at times responsible for the appearance of gastric and intestinal derangements in children; for this reason milk derived from cows afflicted with garget or mastitis is never altogether safe, even when its appearance is entirely satisfactory. Other septic conditions in cows may likewise bring about changes in the quality of the secretion leading to at least temporary reaction in man. The tendency of milk obtained too close to the parturition period to cause looseness of the bowels is also well known.

The Prevention of Milk-Borne Diseases.

Prevention of the entrance of bacteria.-It can very readily be seen from what has been previously stated that an important consideration in the production of milk is to avoid the entrance of dirt and bacteria thereto. At first glance this would seem to be a difficult. procedure and many dairymen have become discouraged over the expense involved and the prospects of its accomplishment. In reality, however, the requirements are exceeding simple, easy of application, and can be put into operation without undue expense. Any

intelligent farmer can in a short time be taught how to produce a clean sanitary milk. The principles involved do not demand that radical changes shall be made in the construction of the stables, the care of the stock, or the installation of expensive apparatus; they simply require that certain rules of cleanliness be enforced, and that the dairyman have in view the object to be attained. The following are the essentials:

1. Healthy stock: Good milk, of safe quality, can be secured only from healthy stock. If cows are diseased, their secretion is apt to contain abnormal constituents or even disease-producing organisms themselves. It is unnecessary to state that milk of this character should never be used by man, and that the tuberculin test and every other precaution should be exercised to prevent the distribution of such supplies. Gastroenteritis in cows, septic fevers, inflammation of the udder, and the presence of any one of a number of other diseases is invariably sufficient reason to warrant the discontinuance of the milk as a food.

2. A careful milker: Milk that comes in contact with the hands of the ordinary milker is not clean, and the danger of producing disease in this manner is evident. The hands should first be thoroughly washed before the milking is begun, carefully dried, and kept dry during the milking process. The milker should avoid the raising of dust and should prevent the entrance of organic matter into his containers. Carelessness in coughing, sneezing, and the dissemination of secretions is also to be avoided.

3. Only covered or hooded milking pails should be used. The hooded pail prevents the entrance of organic matter from the cow, the milker, and the dust contained in the air, and if it is not used the production of clean milk is impossible. So long as material of this character is intercepted by a properly constructed hood it is free. from danger; once it gains access to the milk the harm has been done. The hooded milking pail, with an aperture not over 5 inches in diameter, is therefore to be considered a most important apparatus in the production of clean milk.

4. Sterile containers only should be used. This applies to milk pails, milk cans, strainers, or any other substance with which the milk comes in contact. The ordinary method of washing utensils with soda or soap powder removes dried milk and other gross matter, but does not kill the bacteria which are constantly present. To accomplish this the long-continued application of either steam or boiling water is necessary, the mere rinsing with hot water practiced by the average housewife not being sufficient. After the containers are washed and sterilized, they should be kept in places sheltered from dust.

5. The milk should be properly refrigerated. The equipment necessary for cooling milk either at the dairy or elsewhere is exceedingly simple. An ordinary wooden tub or half barrel supplied with running water at a temperature not above 45° F., or filled with ice water, is all that is necessary. The rapid mechanical coolers are not required; in fact, they but increase the chances of contamination.

To those who are informed it is obvious that many of the steps. commonly recommended for the production of clean milk are not enumerated in the above. For example, nothing is said regarding the cleanliness, ventilation, and lighting of the stable, its freedom from manure, the construction of floors, and the character of the milk house. In so far as these conditions have a bearing upon the health of the stock they are worthy of consideration, as in this way they indirectly affect the quality of the milk. They are also more or less of an indication of the care and cleanliness exercised in the production of pure milk. At the same time they are not essential to that production. It is possible to produce clean milk from cows which have not been carefully groomed and in stables which have not all modern equipment. If the dairyman adheres to the principles laid down regarding the health of his stock, the use of the hooded pail, the sterilizing of containers, and the refrigeration, and exercises due care, he will at least produce a fairly clean milk even if the remaining conditions are not distinctly favorable to such production. It is true that as much depends upon the milker as upon the condition of the stable, or perhaps more. However, a careful, clean dairyman will not maintain a dirty cow shed or stable.

In the transportation of milk the principles which have been outlined should also obtain. The cans should be well jacketed and not allowed to stand in the sun at any stage of their journey. During the summer season refrigeration is necessary. Supplies which are not afforded this treatment, even if perfectly sweet, should be regarded with some suspicion. Fortunately, in many instances modern transportation facilities have been of untold benefit in enabling milk to reach the consumer in a fresh and satisfactory condition, although a supply may be hauled several hundred miles before it arrives at its destination. In distributing plants even greater cleanliness and care should be exercised than at the dairy.

Milk should always be purchased in bottles and never in bulk. In progressive cities the retailing of dipped milk has been prohibited and an important source of disease conveyance thus eliminated. Bulk store milk invariably shows a much higher bacterial count and is more subject to contamination than that supplied in bottles which is distributed to the consumer or purchased in stores. With dipped store milk there is often a lack of care in both the cleaning and sterilization of utensils, usually because the facilities for this work

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