THE BACTERIA OF SOIL, AIR, WATER, ETC. 153 



mentation. Specialists in children's diseases attribute to al- 

 terations in milk with the formation of poisonous substances 

 a preeminent influence in the production of the intestinal dis- 

 orders of infancy so common in the summer. 



Poisoning with milk, ice-cream or cheese is not rare, as is 

 well known. There are many records of whole companies 

 of individuals having been taken violently ill after having eaten 

 one of these feeds from the same source of supply. The symp- 

 toms in such cases resemble those produced by irritant mineral 

 poisons such as arsenic : nausea and vomiting, vertigo, 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 prostration 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 holds 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 for 

 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, organisms possessing 

 very resistant spores the hay bacillus and the potato bacillus- 

 are apt to be present in milk, and these are not killed by any 

 process to which the milk should be subjected for infant 

 feeding. Least of all does sterilization purify milk in which 

 bacterial poison has already formed. 



In regard to the destruction of the tubercle bacillus in milk 

 Glinther*has this to say: Morgenroth found that 10 minutes' 

 heating at 70 C. does not kill the tubercle bacillus, and neither 

 does 2 hours at 55 C. The same authority found that in order 

 to destroy the tubercle bacillus in milk from a tuberculous cow 



*Loc. cit. 



