26 GENERAL CONDITIONS AFFECTING BACTERIA IN MILK 



though they may prevent further contamination or multiplication 

 by clean manipulation and refrigeration.^ The milk problem, there- 

 fore, in all great cities, is to furnish milk in a condition suitable for 

 food after it has been kept twenty-four or thirty-six hours. 



Lastly, many are the advantages given to bacteria after arrival 

 of milk at its destination. In milk-shops, and in the house, there 

 are not a few risks to be added to the already imposing category. 

 Water is sometimes added to milk to increase its volume. Such 

 water, unless sterilised, will add its own contribution to the flora of 

 the milk. Again, in small houses — or homes perhaps of only one 

 room — where the milk stands in unsterilised vessels for some hours, 

 it is impossible to suppose that pollution is avoidable. In such 

 dwellings, milk runs the risk of being contaminated with bacteria, 

 and every kind of dust and dirt, from a hundred different sources. 

 Particularly is this so in the one-room dwellings of London and 

 other large cities, where the cooking, eating, sleeping, cleansing, and 

 sometimes even trade employment, are all conducted, for the entire 



^ The quantity of milk and cream daily conveyed into New York City to 

 supply the wants of its 3J million inhabitants is, according to a recent estimate 

 of the local board of health, about 1,230,000 quarts. From 85 to 90 per cent, of 

 the total is carried by the railroads, the remainder being taken in by waggons 

 from the suburban districts, or supplied by herds within the city itself, the latter 

 embracing altogether some 23,200 cows. The milk transported by rail has its 

 origin in the States of New York, New Jersey, Pennsylvania, Connecticut, and 

 Massachusetts, and some of it is conveyed as far as 350 miles. Much is for- 

 warded from the northern and north-eastern sections of New York State, and 

 it is noteworthy that in some cases consignments destined respectively for New 

 York City in the east and Buffalo in the west originate only a dozen miles apart. 

 Steamers calling at places on the Hudson River carry about 40,000 quarts of 

 milk and cream into New York every day. There are, however, some districts 

 from which the shipments, formerly very large, have almost or entirely ceased. 

 From Long Island, for example, the quantities sent by rail have steadily declined 

 from 6i million quarts in 1885 to practically nothing in 1901. This is largely 

 due to the intensive cultivation of market garden crops, which has developed 

 into an industry far more profitable than dairying. A less important cause of 

 the practical disappearance of this supply is the steady absorption of farms 

 adjacent to New York City into suburban villages, a movement which has taken 

 place to a remarkable degree within the last five years. Baggage cars, re- 

 frigerator cars, and cars specially constructed for the purpose, are employed in 

 the transportation of milk, each railway adopting the style of car best suited to 

 its own requirements. A large milk car will hold 325 cans of 40 quarts each. 

 Most stations where there is a large milk traffic have covered receiving stations, 

 or cooling vats containing ice. By this means milk is reduced to 40° F. in about 

 40 minutes, and ready for immediate transference to the refrigerator cars of 

 the train. The freight vats are not uniform, not all the lines having adopted 

 "the zone system " recommended by the Interstate Commerce Commission. 



