INFLUENCE OF HEREDITY. 195 



tubercular food, such as the meat of tubercular cattle, or 

 through the drinking of milk containing the bacillus. In- 

 testinal tuberculosis or tuberculosis of the mesenteric and 

 retroperitoneal lymph-glands is seen more frequently in 

 infants than in adults. The infection may occur through the 

 mother's milk, or through cows 7 milk if the child is being 

 raised on the bottle. The large number of cases of tabes 

 mesenterica in children confirm this statement. Primary 

 intestinal tuberculosis in adults is not so common. The 

 infection is usually a secondary one, and is the result of 

 the swallowing of tubercular sputum. The danger of infec- 

 tion following the ingestion of tubercular meat is not nearly 

 so great since the attention of the public has been called 

 to the necessity of thoroughly cooking all food. Adults are 

 not in the habit of consuming large quantities of milk, nor 

 are they obliged to depend upon milk for their sustenance as 

 is the child. This fact has led many clinicians to make the 

 erroneous statement that primary intestinal tuberculosis is 

 never met with in the adult ; that it is always secondary to 

 pulmonary tuberculosis. Yet undoubted cases of primary 

 intestinal tuberculosis are on record. 



Milk must be recognized as an important factor in the 

 spread of tuberculosis, and the oft-repeated admonition to 

 sterilize milk before using is not without reason. If a 

 cow is tubercular, no matter where the lesion is situated, 

 whether in the udder or elsewhere, its milk is very liable to 

 contain the tubercle bacillus. A tubercular mother should 

 never be allowed to nurse her child, and when the child is 

 fed on cows 7 milk the milk should always be rendered sterile 

 before using. From the intestinal canal the infection may 

 spread to other parts of the body. 



Heredity : The hereditary transmission of tuberculosis is 

 still a matter of dispute. A few cases have been reported in 

 which infection took place through the placenta ; also two 

 cases of placental tuberculosis. These findings have been 

 confirmed experimentally in animals. It is extremely doubt- 

 ful that infection ever occurs from the father, even when he 

 is suffering from tuberculosis of the testicle or seminal vesi- 

 cles, although he may infect the wife. It is self-evident, 



