diet even for the adult, not only supplying heat and energy but also tissue.

One of the most valuable by-products of the war that we have just passed through is the wealth of information that has been furnished us in regard to the relative values of foods, the necessity for a balanced diet, and the knowledge of the importance of accessory food factors or vitamins, which are now known to be so essential for a properly balanced diet.

DANGERS OF MARKET MILK.

It is a well-recognized fact, fully demonstrated, that ordinary market milk is a very significant source of the transmission of disease germs to man; in fact, milk constitutes the channel through which probably more disease is transmitted than all other foods and drinks combined, inasmuch as we have to contend not only with one particular disease, peculiar to both the dairy cow and to man, but also with the possibilities of transmission of other communicable diseases through contamination by those persons handling the milk.

BOVINE TUBERCULOSIS.

The late Professor Koch, to whom we are indebted for the discovery of the tubercle bacillus, which is responsible for tuberculosis, for years maintained that this germ in man and beast was identical. However, in 1901, at the International Congress on Tuberculosis, held in London, Koch took the stand that bovine tuberculosis was harmless to man. This statement was regretted by many. It came like a bolt from the blue. However, in my judgment, it was probably one of the most valuable statements that Professor Koch ever made, inasmuch as I question whether we would have been placed in possession of the indisputable evidence of the dangers of this disease to man at as early a date as we were had it not been for this incident. Immediately following this convention, at which Koch promulgated this opinion, commissions were appointed by England, Germany, France, and the United States, authorized by their countries to investigate and report findings to the congress at its next meeting. The findings of these various commissions were intensely interesting, as they practically all demonstrated beyond question that 251 per cent of all cases of tuberculosis in children under 16 years of age of the bovine type, and is transmitted, for the most part, through the medium of milk.

SOURCES OF CONTAMINATION AND HOW TO PREVENT THEM.

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In addition to bovine tuberculosis as a menace to man, numerous outbreaks and epidemics of diphtheria, scarlet fever, typhoid fever, septic sore throat, and, in fact, practically all communicable diseases, have been traced directly to the milk supply. Yet this is all preventable by scientific Pasteurization. Obviously, then, the failure to adopt the necessary means of preventing these diseases by any community or municipality surely means criminal negligence on the part of the authorities. Milk supervision must begin with the cow,

and the environment of the cow, and end with the consumer. From the cow's udder to the infant's stomach there are from 20 to 25 possibitilies of contamination of this most valuable food and the most important source of contamination, or responsibility for contamination, is the man. It is surprising what an excellent quality of milk can be procured from uninviting surroundings, providing the man in charge of the production of this milk, and responsible for it, has an aseptic conscience and a proper conception of personal hygiene, personal cleanliness, and of his obligations to his fellowmen in doing his bit toward preventing the spread of the aforesaid communicable diseases.

With a well-organized milk supervision from the cow to the consumer we can guarantee a clean milk supply, for the most part free from barnyard contamination. However, it must be remembered that this does not mean a safe milk supply. The milk of any community can be made safe at all times only by rendering it bacteriologically clean or bacteriologically safe by scientific Pasteurization; that is, raising the temperature of the milk to 145° F., and holding it at that temperature for thirty minutes, and then promptly chilling to 45° F., and retaining it at or about that temperature until delivered to the consumer. This process will destroy all disease-producing germs without materially changing the nutritive value, chemical composition, or digestibility of the milk. However, we must first insist that all milk be free from barnyard contamination, free from all mechanical sediment, as demonstrated by the sediment test, before we can consider it suitable milk for Pasteurization, bearing in mind that Pasteurization will not make dirty milk clean. Pasteurization is intended only to make clean milk bacteriologically clean. Pasteurization must be made safe by installing self-registering thermometers of an approved type in connection with every Pasteurization plant, or in other words, "making the process fool-proof." In Toronto these self-registering thermometers are owned and controlled by the department of public health, and we carry the keys. They are so constructed that they can not in any way be tampered with. We have had all of them tested by the Federal Government authorities at Ottawa, and we have them retested from time to time by a thermometer that is known to be accurate.

OBJECTIONS RAISED TO PASTEURIZATION.

The objections to Pasteurization are for the most part a pitiful exposition of ignorance on the part of the objectors, and consequently when I refer to the advisability or inadvisability of Pasteurization, I do so with apologies to my colleagues, especially those on the commission of milk standards, to whom the discussion of this problem is ancient history. No one who has been making a scientific study of the milk problem and who is, therefore, in a position to give an intelligent opinion, has, within the past 15 years at least, questioned for a moment the advisability of Pasteurization of all milk for infants and children, and even for adults. This is true especially if the milk does not come up to the standard required for certified milk, and even certified milk should be Pasteurized in order to make it at all times safe.

In all the advances in science there are always a few persons who can not keep pace with the advancement, and they expect others to wait for them. As Sir William Osler expressed it, it is necessary therefore to reiterate, reiterate, and reiterate, and continue, until the densest mind has been able to appreciate the indisputable evidence.

It is true that there is one argument against Pasteurization that may be raised and that is that the process of Pasteurization affects, in a degree only, the antiscorbutic vitamin. However, it has no other ill effects on the milk, either in regard to its chemical composition, its food value, or its digestibility. Also, even this antiscorbutie vitamin is not a stable constituent of milk and its presence depends greatly, as already pointed out, on the fodder of the herd. Furthermore, any little ill effects that may result from Pasteurization in this respect can be promptly eliminated by the administration of orange juice or tomato juice, both of which are abundantly rich in the antiscorbutic vitamin. All modern pediatritians recommend that, as a routine, infants be given a certain amount of orange juice every day: but no amount of orange juice will counteract or destroy the results of contamination of milk by the various disease-producing germs. There have been between 500 and 1,000 outbreaks of typhoid fever, scarlet fever, diphtheria, septic sore throat, as well as other communicable diseases on this continent within the past few years. These particular outbreaks or epidemics would never have occurred if the milk supply had been scientifically Pasteurized.

HOW CAN WE SAFEGUARD OUR MILK?

The control of the milk supply commences with the examination of every animal in the herd. All cows from which milk is to be used for human consumption should be examined by a veterinary inspector of the department of public health, and any animal found to be suffering from any form of disease should be excluded from the herd. A similar inspection should be made of all producing herds on an average of twice a year. It probably will be found impossible or impracticable to apply the tuberculin test to all cows producing milk for any large city. The magnitude of this task must be apparent, but any cows obviously suffering from tuberculosis should be promptly removed from the herd.

The inspection service maintained in the country by a department of health should be of an educational character. The veterinary inspector should assist the farmer in every way possible in the ways and means of producing clean milk, and also advise him of the importance of keeping a separate account for each animal in the herd: the amount of food consumed daily; the amount of milk given daily; the percentage of cream; and the total solids, and in this way, they will be enabled to eliminate from their herd those animals that are intended for beef and not for dairy purposes, which help to reduce materially the profit on any herd. When a farm is visited, the condition of the stables, barn, milk house, cattle, and utensils should all be carefully investigated, as well as the methods of milking; the precautions taken in cleansing the udder and flanks of the cow before the process of milking begins; the subsequent prompt chilling of the

milk before it is shipped to the city; and the importance of proper and efficient ventilation, not only to safeguard the milk supply but also to safeguard the animals, thus assuring the farmer that he can not afford to disregard the proper housing of his stock. Especial attention must be given to the efficient screening of all milk houses and the cleansing and sterilization and subsequent care of all milking utensils.

Where the conditions on the farm are such as to convince the inspector that safe milk can not be produced at all times, the supply should be excluded from the city. No procedure is more effective in having a producer comply with the requirements of a department of health than to exclude his supply until such conditions are corrected. To the credit of the farmers, I might say, it has been our experience that a great majority of them welcome the inspectors and carry out their suggestions quite willingly. A certain number do not. However, if after repeated efforts to improve, the requirements of the department of public health are not carried out, these men are promptly excluded. We are careful not to require anything of a producer in the form of any unnecessary expense in connection with his buildings or equipment. There are a few things which should, however, be insisted on, such as tight flooring; clean whitewashed stables, with efficient light and ventilation; a separate milk house, lighted and used for milk only; an adequate supply of cold water or ice for chilling the milk is also most essential. Other animals must not be allowed in the dairy stables. Throughout the whole inspection service, the fact should be particularly emphasized that the production of clean milk is dependent for the most part on the clean habits and sanitary conscience of the producer.

There are, of course, a certain number of producers who will not meet the requirements until pressure is applied, although fortunately this number diminishes year by year. In some instances it will be found that inspectors have repeatedly asked that certain minor improvements be made, and that even letters from the office have produced no response; but within 24 hours after exclusion, frequently long-distance telephone calls from producers have been received. stating that cows have been clipped, or stables have been whitewashed, or some similar requirement complied with which they had failed to carry out before.

It is extremely important to have every dairy farm intending to ship milk to the city inspected before any milk is received, in order that a farmer may not be able to ship dirty milk for several weeks before the inspector visits his farm. When a producer has been excluded for dirty milk or insanitary conditions on the farm, a reinspection should always be made before he is allowed to resume shipping. At this inspection the inspector should insist that everything the farmer has been asked to do before has been complied with, and usually few who ask for reinspection find the demands of the department of health at all burdensome.

A great deal of the milk supply of every city, in recent years, comes through shipping stations. In the case of Toronto, approximately 25 per cent of the milk supply of the city is sent through stations. In most of these shipping stations the milk is pooled daily and shipped in refrigerator cars to the city. In others, the milk

is chilled in the original cans and then reshipped. In the stations where all milk is pooled or mixed, it is quite evident that the identity of the milk is lost, so that it has been necessary for inspectors to visit these stations to make sediment tests and to take samples for butterfat and bacterial count. This is usually done with the assistance of the veterinary inspectors of the particular districts. The sediment disc, taken on the spot and in the presence of the producer and his neighbors, forms a very striking object lesson on clean and dirty milk production. When inspectors stay two days or more at a station, the improvement among the careless shippers is usually quite marked. Pressure should be gradually brought to bear on these shipping stations to control their own supply more adequately, and our experience in Toronto, at the present time, is that some of our shipping stations are shipping the cleanest milk that is being sold in the city, inasmuch as they are making the necessary demands on the farmers sending the milk to their particular stations. While these shipping stations have the disadvantage of compelling supervision of the supply some distance out of the city, they have a much greater advantage, which offsets this, and that is, that the milk is chilled thoroughly and held cool until delivered to the city.

Part of the supply from the area adjoining the city comes in trucks. These trucks must be covered to keep the milk cool in summer, and they should be inspected regularly to see that this is done, and also to see that they are not bringing in milk from excluded farmers to dairies other than those to which the supply was formerly sent.

CONTROL OF DAIRIES WITHIN THE CITY.

It is at the dairies in the city that a large part of the control of the milk supply itself must be exercised. We require the dairies in the city to own and control all milk cans. After these cans are emptied they are thoroughly washed and sterilized by means of live steam and then sealed before being sent back to the farmer. When the farmer is prepared to pour milk into them, and not until then, is this seal broken, and after he has filled his cans, he again, in turn, seals them before shipping to the city or to the shipping station.

When the milk is received in the city, the first step after agitating the contents of the can, is to filter through a cotton disc a small quantity, usually a pint. The cotton disc, through which this pint of milk is filtered retains all dirt or impurities, which stand out in striking contrast to the white background on which they rest. This sediment test has been of valuable assistance in directing the activities of the outside inspectors to farms where conditions are not satisfactory. Milk which shows any appreciable amount of sediment should be promptly condemned and either stained with a nonpoisonous dye and returned to the farm, or emptied into the sewer. While it is not possible, for obvious reasons, to inspect every can of milk in the city, yet inasmuch as the producer knows that our inspector may open any one of his cans for inspection, he is usually as careful as if he knew that every can was going to be inspected."

The second procedure is the taking of the temperature. This is particularly important in the summer weather, because milk which has reached the temperature of 75° F., or 80° F., we know has not