456 BACTERIA PATHOGENIC TO MAN 



4. The so-called "gelbe gait," or contagious mammitis of European 

 writers, appears to be merely a severe form of mammitis due to a variety 

 of streptococcus which, on account of its chromogenic properties, gives 

 to the milk its peculiar golden-yellow color. 



Our failure to discover definite pathogenic bacteria in milk, as well 

 as the numerous varieties of bacteria met with, have forced us to rely 

 on the clinical observation of infants to note what difference, if any, 

 occurred in those fed on raw and Pasteurized milk from the same source, 

 and upon different milks of unknown origin varying in the number of 

 bacteria contained. These observations were combined with those upon 

 other factors which influenced the health of the infants. 



Heated Milk vs. Raw Milk for Infants. During each of the summers 

 of 1902, 1903, and 1904 a special lot of milk was modified at one of the 

 Straus depots for a group of fifty infants, all of whom were under nine 

 months of age, and distributed daily in the usual way. To one-half the 

 infants the milk was given raw; to the other half Pasteurized. 



The modified milk was made from a fairly pure milk mixed with 

 ordinary cream. The bacteria contained in the milk numbered on 

 the average 45,000 per cubic centimetre, in the cream 30,000,000. The 

 modified raw milk taken from the bottles in the morning averaged 

 1,200,000 bacteria per cubic centimetre, or considerably less than the 

 ordinary grocery milk; the Pasteurized, about 1000; taken in the late 

 afternoon of the same day they had respectively about 20,000,000 and 

 50,000. 



Twenty-one predominant varieties of bacteria were isolated from 

 six specimens of this milk collected on different days. The varieties 

 represented the types of bacteria frequently found in milk. The infants 

 were selected during the first week in June, and at first all were placed 

 on Pasteurized milk. The fifty infants which had been selected were 

 now separated into two groups as nearly alike as possible. On the 15th 

 of June the milk was distributed without heating to one-half the infants, 

 the other half receiving as before the heated milk. In this way the 

 infants in the two groups received milk of identically the same quality, 

 except for the changes produced by heating to 165 F. for thirty minutes. 

 The infants were observed carefully for three months and medical 

 advice was given when necessary. When severe diarrhoea occurred 

 barley-water was substituted for milk. 



The first season's trial gave the following results: Within one week 

 20 out of the 27 infants put on the raw milk suffered from moderate 

 or severe diarrhoea; while during the same time only 5 cases of moderate 

 and none of severe diarrhoea occurred in those taking Pasteurized milk. 

 Within a month 8 of the 27 had to be changed from raw back to heated 

 milk, because of their continued illness; 7, or 25 per cent., did well all 

 summer on raw milk. On the other hand, of those receiving the Pas- 

 teurized milk, 75 per cent, remained well, or nearly so, all summer, 

 while 25 per cent, had one or more attacks of severe diarrhoea. There 

 were no deaths in either group of cases. 



During the second summer a similar test was made' with 45 infants. 



