80 CITY MILK SUPPLY 



As long ago as 1895, Kober pointed out that the house fly might infect 

 milk; since that time knowledge of the habits of that insect has increased 

 and it is generally recognized to be a factor in spreading typhoid fever, 

 tuberculosis and other diseases. By preference it lays its eggs in horse 

 manure, but it also oviposits in human excrement and cow dung. Fur- 

 thermore, it feeds on human dejecta so that it carries away from the ordure 

 on its bedraggled legs and in its infected intestines such disease germs as 

 happen to be therein and it tracks or drops them on whatever it happens 

 to alight. Flies also have the habit after feeding on liquid food of 

 exuding drops of fluid from their proboscides. These drops are some- 

 times sucked up again and sometimes are deposited on the surface on 

 which the flies are walking. This deposited material is derived from the 

 fly's crop; it is sometimes called " vomit" and maybe infectious. In feed- 

 ing on dry material the fly moistens it with vomit or saliva; this is done 

 for instance when it feeds on sugar. Flies swarm about milk pails, in 

 stables and in milk houses and wherever milk is handled, so that great 

 care should be taken to screen such places and to fight the flies with 

 sticky fly paper, traps, etc., but poison fly paper should not be tolerated 

 about a dairy. While it is difficult to prove that flies have infected the 

 utensils or milk of any dairy it is a fact that they have been strongly 

 suspected of doing so. Consequently great care should be taken to 

 make privies on dairy premises fly proof . Also, employees should not be 

 allowed to defecate on the ground near the dairy nor should stools be 

 thrown on the manure heap. Likewise, the house slops should be prop- 

 erly disposed of and not thrown out on the ground where flies can get 

 at them. 



In some dairies cats are given free run of the barns to catch mice; 

 they are apt to be much in evidence at milking time and are not slow to 

 get at a pail of milk that a milker sets down for a moment. Rarely, cats 

 become infected with diphtheria and possibly other disease and there 

 is a bare chance that this might happen with unhappy consequences in 

 a dairy. 



Infection of Milk Enroute to the Creamery or City. After milk 

 leaves the farm there is the chance that it may be infected on the way to 

 the creamery or railroad station or in the course of the journey to the 

 city if the cans in which shipment is made are unsealed. In some com- 

 munities milk is picked up from several farms by a single driver and 

 hauled to its destination. There is apt to be more or less shifting about 

 of the cans on the trip and there may be some dumping of milk from one 

 can to another so that if the handler should happen to be a carrier or 

 diseased, the milk might get infected. 



On the trip to the city unsealed cans are apt to get opened and the 

 contents may even be sampled by the curious. This is more likely to 

 happen in trolley and baggage cars to which the public has access than 



