TUBERC V LO-INFECTION OF MAN. 
563 
there is greater proliferative, protective activity in the gland-tis¬ 
sue of young animals), but commonly pass through those of 
adult animals, and then cause primary pulmonary tuberculosis; 
that tubercular processes of the lung never begin in the bronchi 
or alveoli, but constantly in the capillaries, especially in the finest 
capillary network of the subpleural tissues, etc. 
The capillary system of the lungs is a double system—a deep, 
penetrating system—and a superficial sub-pleural system, hence 
tubercular pleurisy so common. But Aufrecht’s work relative 
to this localization of the earliest lesions of pulmonary tuberculo¬ 
sis is really conclusive. Here it is: “ First, the initial changes of 
the apices of the lungs, as I have convinced myself, by repeated 
anatomical examination, do not spread from the terminal 
branches of the bronchi, and, second, the cheesy tubercle in the 
lung is associated not with the finer branches of the air-tubes, but 
with the terminal capillaries of the pulmonary arteries.” 
And while not especially an advocate of the intestinal route 
as the sole mode of infection, he ends his article here referred to 
with these words: “ The inhalation theory for lung tuberculosis 
is no longer tenable.” ( Kohler .) 
Orth makes the statement that even with localized tuberculo¬ 
sis in the lymph glands and the lung, we cannot exclude the intes¬ 
tine as the portal of entry of the tubercle bacillus. At the Inter¬ 
national Conference, held in Vienna during September, 1907, he 
said the tubercle bacilli can enter the body from the intestinal 
canal, which might itself, however, remain completely unaffected. 
Moreover, from the prophylactic point of view, the channel of 
infection was of only secondary importance, as the object to be 
aimed at was the destruction of all sources from which infection 
might take place. And as sources of infection he named milk 
and butter from tuberculous cows and sputum from tuberculous 
individuals, and bovine tuberculous he characterizes as undoubt¬ 
edly infectious for human beings. 
Klebs has convinced himself that tuberculosis is a disease of 
the lymphatic system, and may remain such until the end of life, 
and that infection occurs through the intestines, most frequently 
