As prophylaxis against milk infection certain precautions are necessary, and it should be the duty of physicians to educate public sentiment in regard to their importance as a means of restricting the spread of infectious and dietetic diseases.

For transportation from the country to the city, milk is usually taken from the farms in forty-quart tin cans, which should be filled full and tightly covered to prevent churning and souring. Some railways supply refrigerator milk cars, which are hung upon specially constructed springs, to prevent as far as possible agitation of the cans. At some dairies the milk is put, directly after milking, into glass bottles previously sterilised by washing and steaming, which are then tightly corked. If pails, pans, or cans are used, their absolute cleanliness must be insured by frequent careful washing and by occasional scalding with hot water. This destroys germs or ferments which would otherwise contaminate the fresh milk and soon sour it. The bottles are sealed and stamped " Certified Milk " befoe being sent to market.

Many large dairies now employ a veterinarian, whose duty it is to daily examine all the cows and report on their health, and on the hygienic condition of the stables, yards, etc.

Nothing is more disgusting than allowing the manure-besmirched tails of ungroomed cows to contaminate the hands of milkers, or the milk itself, and yet this is constantly happening.

The question of prophylaxis is of such universal interest that the admirable rules formulated by Vaughan are here quoted in full:

"a. The cows should be healthy, and the milk of any animal which seems indisposed should not be mixed with that from the healthy animal.

"b. Cows must not be fed upon swill or the refuse from breweries or glucose factories, or upon any other fermented food.

"c. Milch cows must not be allowed to drink from stagnant pools, but must have access to fresh pure water.

"d. The pasture must be freed from noxious weeds, and the barn and yard must be kept clean.

"e. The udders should be washed and then wiped dry before each milking.

"f. The milk must be at once thoroughly cooled. This is best done in the summer by placing the milk can in a tank of cold water or ice water, the water being of the same depth as the milk in the can. It would be well if the water in the tank could be kept flowing, and this will be necessary unless ice water is used. The tank should be thoroughly cleaned each day to prevent bad odours. The can should remain uncovered during the cooling and the milk should be gently stirred. The temperature should be reduced to 6o° F. or lower within an hour. The can should remain in cold water until ready for delivery.

"g. Milk should be delivered during the summer in refrigerated cans or in bottles about which ice is packed during transportation.

"h. When received by the consumer it must be kept in a clean place and at a temperature some degrees below 6o° F.

"If all the milk used in the artificial feeding of infants could be obtained and marketed with the care demanded by the above rules, milk infection would be practically unknown and the sterilisation of the infant's food would be unnecessary".

Laws relating to the marketing of milk have been enacted in 39 States, which comprise such improvements as are summarised in the following list, compiled by the Journal of the American Medical Association (September 19, 1903):

"The registration of all dairies; official indorsement of properly conducted dairies; inspection of all herds, barns, dairy buildings, etc., once a month; better lighting, ventilation, drainage and cleanliness of cow stables; whitewashing the interior of stables; eradication of tuberculosis from dairy herds; branding of condemned cows; cows not to be given swill feed, etc.; cows to be regularly cleaned; pasturage for city cows; aeration of milk in pure air; prompt cooling of milk and holding it at low temperature until final delivery; shipment of milk promptly from farms after milking; delivery of milk and cream in sealed packages (glass bottles or small cans), so as to avoid unnecessary contamination by city dust, etc.; delivery of milk in cities at any hour of the day when it can be supplied in the best condition; restrictions on the sale of milk in markets, candy stores, etc.; delivery of milk from such stores in bottles only; mixing of herd milk so as to get an article of uniform composition; bottling of milk only at the dairy or place of general supply; daily sterilisation of milk utensils; more rigid inspections for preservatives in milk; chemical and bacteriologic examinations of milk; standards for cream and skim milk".

The enactment of these laws is due to the activity of the medical profession, and has largely been accomplished through the influence of county, state, or other medical societies and boards of health, which latter are responsible in most instances for their enforcement.