78 PRINCIPLES AND PRACTICE OF MILK HYGIENE 
type of the organism was determined by others, a total of 
1511 cases. There were 955 cases in individuals over 16 
years of age, 177 in children between 5 and 16 years, and 
368 in children under 5. Tubercle bacilli of the bovine 
type were found in 35 per cent. of the cases in children 
between the ages of 5 and 16, and in 26 per cent. of the 
cases in children under 5. In addition to these, there were 
eleven cases in which both types of bacilli were found. 
It is usually difficult to discover the source of infec- 
tion in cases of tuberculosis in man because the disease 
does not become apparent for a long time after exposure 
to infection has occurred. Nevertheless, there are a 
number of cases recorded of tuberculosis in children and 
adults using milk from tuberculous cows for which no 
other source of infection could be found.® Regarding the 
evidence in these cases as generally incomplete, Koch, in 
1902, suggested that a search be made for cows in which 
tuberculosis of the udder could be positively diagnosed 
and, when such cases were found, that it be ascertained 
how long the disease had existed, who consumed the milk 
or its products, whether the milk was used raw or cooked, 
and if the persons who used the milk or its products were 
infected with tuberculosis. Between 1905 and 1909 
Weber and Ungerman’ found in Germany 69 cases of 
udder tuberculosis concerning which the information de- 
sired could be obtained. Three hundred and sixty per- 
sons, including 151 children, used milk from these cows. 
Two boys were affected with tuberculosis of the cervical 
lymph glands in which bacilli of the bovine type were 
® Rievel, Milchkunde, pp. 107-108. 
7 Cited by Ostertag, Zeitschr. fiir Fleisch u. Milchhygiene, 
pp. 26 and 27, No. 2, vol. xxiii; p. 123, No. 6, vol. xxiv. 
