508 Tuberculosis. 



Gastric juice at 30° 0. does not affect the bacilli in 3 to 4 hours. In the 

 course of 6 or 8 hours, however, their virulence becomes reduced and in 18 to 24 

 hours they are destroyed (Zagari, Strauss & Wurtz). Bile and pancreatic juice 

 do not affect them (Gallichi). 



Pathogenicity. When susceptible animals are inoculated 

 Bubcutaneously with tuberculous secretions, tissue or virulent 

 cultures, there develops at the point of inoculation a tumor 

 which may break in the course of a few days, discharge a caseo- 

 purulent mass and develop into a sinuous ulcer. In some cases 

 the ulcer will heal and the process terminate; in other cases 

 the disease progresses. After a time the lymphatic glands 

 which are supplied by the lymph- vessels of the affected region, 

 swell and become the seat of the formation of tuberculous foci, 

 which, in the course of time, undergo cheesy degeneration. 

 Following this the internal organs become affected almost 

 simultaneously, sometimes one after another along the lymphatic 

 circulation and at other times apparently independently through 

 the medium of the blood. Cutaneous inoculations (rubbing on 

 the scarified skin) usually produces only small rapidly healing 

 nodules (Chauveau). Sometimes, however, the neighboring 

 lymph glands become involved and a general tuberculosis may 

 follow (Courmont, Babes, Osman Nouri). 



'. After intraperitoneal inoculation to which animals in 

 general are very susceptible, the peritoneum (especially the 

 mesentery) the abdominal lymph glands, the spleen and the 

 liver are attacked first. Adjacent organs may become involved 

 later. The most effective method of inoculation consists in 

 the injection of virus into the jugular vein. This is followed 

 by the development of innumerable tubercles in the lungs with 

 acute swelling of the lymphatic glands of the thoracic cavity. 

 Animals usually die in the course of a few weeks with symp- 

 toms of high fever and rapid emaciation. Sometimes other 

 organs are similarly affected. If inoculation is made in the 

 anterior chamber of the eye, typical tuberculosis develops in 

 the iris in the course of two or three weeks. This local affec- 

 tion is then followed by a general tuberculosis (Cohnheim, 

 Baumgarten). 



The feeding or ingestion of pure cultures or of material 

 containing tubercle bacilli (sputum, milk tissue) to guinea pigs 

 or calves is followed either by tuberculosis of the peripharyn- 

 geal, cervical and mediastinal lymph glands and bronchial tubes, 

 or by an infection of the mesenteric lymph glands and the ab- 

 dominal organs. The pharyngeal and intestinal mucous mem- 

 brane may remain practically healthy but on the other hand, 

 especially if the infection was severe, the tonsils may ulcerate 

 or the lymph follicles of the intestines may undergo tuberculous 

 ulceration. Old animals are only rarely affected by these means. 



Inhalation of dry or pulverized tuberculous tissue or secre- 

 tions as well as culture sprays may be followed by tuberculosis 

 of the lungs and of the bronchial glands. The more finely the 

 infectious material is pulverized or divided the greater are the 



