MILK-BOHNE INFECTIONS 443 



York State. The authors tabulated 905 cases, and came to the 

 conclusion that, "for the most part, the disease was spread by 

 contact and in prosodemic fashion, but a small milk or cream epi- 

 demic was superimposed upon the general prosodemic spread of 

 the disease." Krumwiede and Valentine came to similar con- 

 clusions. 



Pathogenic streptococci have no great resistance to heat and 

 are probably destroyed by pasteurization temperature. Pas- 

 teurization of milk is, therefore, the most effective method of 

 prevention of this disease. 



Human Tuberculosis. — Dissemination of human tuberculosis 

 through milk is conceivable, although it does not seem to happen 

 frequently. Clear records of this mode of transmitting tuber- 

 culosis are not available, and the insidious onset of the disease, 

 together with the uncertain incubation period, render exact ob- 

 servations difficult. 



However, a tuberculous employee engaged in milking or hand- 

 ling milk might spread the infection by coughing, sneezing, or 

 direct contact of his hands. 



Asiatic cholera is essentially an intestinal disease, and the 

 possibility of the virus entering milk is by no means excluded. 

 However, actual cases of cholera resulting from milk infection are 

 rare, probably because the spirilla die rapidly in milk, and be- 

 cause carriers of the disease are uncommon. 



Scarlet Fever. — A number of epidemics of scarlet fever have 

 been traced to milk-supplies, but the method of dissemination is 

 not quite clear owing to our ignorance of the causal organism. 

 It has been believed that the virus might be derived from the 

 cow, but there is no conclusive evidence to this effect. 



More probable is infection of bottles or utensils either at the 

 farm, by the middleman, or in the home. Milk probably becomes 

 infected with the virus of scarlet fever by contact with persons 

 in early stages of the disease, or from bottles and utensils handled 

 by them. According to Swithinbank and Newman the infection 

 can be carried by garments, toys, books, bedding, etc. Milk 

 infection from these objects is conceivable. Dust probably does 

 not form a serious source of dissemination. 



Investigation of scarlet fever epidemics is carried on in a man- 

 ner similar to that of other milk-borne epidemics. Pasteuriza- 

 tion of milk is an effective preventive measure, as in many other 

 epidemics. 



Poisonous Milk 



Poisoning caused by milk and milk products has been reported 

 repeatedly. Real poisoning may be due to the presence of mem- 



