702 PROCEEDINGS OF SECTION I, 



tubercle bacilli : they can be distinguislied by their morphological 

 character, and by the soil on which they are most easily grown. They 

 are called the bacillus Typus humanus and the bacillus Typus hovinus. 



Cattle are susceptible only to the bacillus Typus hovinus. Swine 

 are susceptible to both varieties of the bacillus, but more especiallv <-" 

 the Typus hovinus. 



Man suffers chiefly from the bacillus Typus humanus, but he is 

 also susceptible to the bacillus Typus hovinus, which he may ingest in 

 meat from tuberculous animals, or in milk from cows suffering from 

 tuberculosis of the udders. 



The risk of infection from boivne tuberculosis is very small in 

 man compared with the risk of infection from a consumptive human 

 .laeing. 



This opinion has been materially strengthened by some interesting 

 experiments that have recently been made upon anthropoid apes. 

 From the nature of the experiment the susceptibility of man to bovine 

 tuberculosis cannot be determined by direct inoculation, but it occurred 

 to Professor Dungern and Dr. Henry Smidt to experiment on anthro- 

 poid apes as being the nearest relatives to man in the animal scale. 



The experiments were carried out in Sumatra upon two varieties 

 of the Gibbon {Hylohates syndactylus and Hylobates agilis). Three 

 animals were inoculated under the skin with cultures of tubercle of 

 human type, and three with cultures isolated from cattle (lOmg.). 

 The animals proved to be equally susceptible to the bacilli of both 

 types ; they all contracted tuberculosis. Next, three Gibbons were 

 fed with cultures of human type, and three were fed with cultures of 

 the Typus hovinus. In each case two out of three animals became 

 -affected with generalised tuberculosis. From these experiments it 

 was concluded that as the Gibbon was equally susceptible to both 

 types of tuberculosis man was probably also susceptible to both human 

 and bovine tuberculosis. (B.M.J., 1906, 11., 721). 



In the present state of our knowledge, then, we must act in the belief 

 that man, especially in infancy, is liable to contract consumption from 

 tubercular cattle. After the hopes that were raised by Professor 

 Koch's announcement, this is a disappointing conclusion, but perhaps 

 in the end it may prove to be to our advantage. Some physicians 

 who have carefully studied the matter affirm that mild boivne tuber- 

 culosis contracted by man in childhood confers a certain immunity 

 against pulmonary consumption in the adult, just in the same way 

 that vaccination protects against smallpox. Indeed Calmette is so 

 convinced that bovine tuberculosis protects man against ordinary 

 consumption that he has even suggested that infants of a few weeks 

 old should be dosed with small quantities of sterilised cultures of 

 tubercle of human and bovine origin, and he prophesies that in this way 

 the child will escape future consumption. Perhaps the day will come 

 when preventive inoculation against consumption will be generally 

 adopted, but we shall require certain proof of its safety and of its 

 •efficacy before we shall be willing to consent to any such treatment. 

 (B.M.J., 1904, II., 907). 



