THE BACTERIA OF SOIL, AIR, WATER, ETC. 135 



of individuals having been taken violently ill after having 

 eaten one of these foods from the same source of supply. The 

 symptoms in such cases resemble those produced by irritant 

 mineral poisons such as arsenic: nausea and vomiting, ver- 

 tigo, dryness of the mouth, sense of burning and constriction 

 in the throat, difficulty in swallowing, cramps and griping 

 pain in the bowels, constipation or diarrhea, general prostra- 

 tion or even collapse. Vaughan isolated from poisonous 

 cheese a ptomaine which he called tyrotoxicon. It appears, 

 however, that other toxins may be present in cheese, and that 

 tyrotoxicon is a somewhat rare poison. Vaughan believes that 

 bacteria of the colon group play an important part in producing 

 poisons in milk and cheese. 



To prevent the alteration by bacteria of milk intended to 

 be the food of infants, the practice of sterilizing milk has been 

 largely in vogue. Unfortunately, during sterilization the milk 

 undergoes some kind of alteration which makes it disagree 

 with certain infants. Furthermore, among the organisms 

 which would be likely to contaminate milk bacteria such as 

 the bacilli of hay and potato, whose spores are so excessively 

 resistant, would be prominent, and they are not killed by any 

 process to which the milk intended for an infant's consump- 

 tion could possibly be subjected in the household. Least of 

 all can sterilization be relied on to purify milk in which bac- 

 terial poisons are already formed. 



The investigations of Park and Holt* show that in New 

 York City the number of bacteria in milk is much smaller in 

 winter than in summer, and has Uttle effect on the health of 

 infants during cold weather; but that in wann weather with 

 milk of average quality the infants who received sterilized 

 milk throve on the average much better than those who received 

 raw milk. 



*Archives oj Pedialrics. December, 1903. 



