458 BACTERIA PATHOGENIC TO MAN 



In a third institution an average grade of milk was used which was 

 heated. This milk before heating contained 2,000,000 to 20,000,000 

 bacteria per cubic centimetre. The institution was an infant asylum 

 in which there were 126 children between the ages of two and five years. 

 There were no cases of diarrhoea during the summer. 



These clinical observations taken in connection with the bacterio- 

 logical examination at the laboratory show that although the milk 

 may come from healthy cattle and clean farms, and be kept at a tem- 

 perature not exceeding 60 F., a very great increase in the number of 

 bacteria may occur. Furthermore, this may occur without the accu- 

 mulation in 'the milk of sufficient poisonous products or living bacteria 

 to cause appreciable injury in children over three years of age, even 

 when such milk is consumed in considerable amount and for a period 

 extending over several months. Milk kept at temperatures somewhat 

 above 60 F. was not met with in our investigations, but the histories 

 of epidemics of ptomain poisoning teach that such milk may be very 

 poisonous. It is also to be remembered that milk abounding in bac- 

 teria on account of its being carelessly handled is also always liable to 

 contain pathogenic organisms derived from human or animal sources. 



Results with Very Impure Milk Heated vs. Those with Pure or Average 

 Milk Heated. During the summer of 1901 we were able to observe a 

 number of babies fed on milk grossly contaminated by bacteria. In 

 1902, systematic supervision of all stores selling milk was instituted by 

 the Health Department, so that the very worst milk was not offered 

 for sale that summer. 



The observations upon the impure milk of 1901 are of sufficient 

 importance to be given in detail, although already mentioned in the 

 report of the observations upon infants of both summers which were 

 fed on "store milk." A group of over 150 infants was so divided that 

 20 per cent, were allowed to remain on the cheapest store milk which 

 they were taking at the time. To about the same number was given 

 a pure bottled milk. A third group was fed on the same quality of 

 milk as the second, but sterilized and modified at the Good Samaritan 

 Dispensary. A fourth group received milk from an ordinary dairy farm. 

 This milk was sent to a store in cans arid called for by the people. A 

 few infants fed on breast and condensed milk were observed for control. 



In estimating the significance of the observations recorded in the 

 tables, one should bear in mind that not only do different infants possess 

 different degrees of resistance to disease, but that, try as hard as the 

 physicians could, it was impossible to divide the infants into groups 

 which secured equal care, and were subjected to exactly the same con- 

 ditions. It was necessary to have the different groups in somewhat 

 different parts of the city. It thus happened that the infants on the 

 cheap store milk received less home care than the average, and that 

 those on the pure bottled milk lived in the coolest portion of the city. 

 Certain results were, however, so striking that their interpretation is 

 fairly clear. It is to be noted that the number of infants included in 

 each group is small. 



