292 MANUAL OF BACTERIOLOGY. 



of the intestines there is also tuberculosis of the mesenteric 

 lymph-nodes. The disease may travel along the serous surfaces 

 and become widely scattered throughout a cavity Hke that of 

 the pleura or peritoneum. The bacilh may be expelled on 

 some mucous surface and be carried along it to infect some 

 point farther on, as happens when the larynx becomes infected 

 in tuberculosis of the lungs, and when in the same disease 

 tuberculous sputum is swallowed and leads to infection of the 

 intestines. Finally, the infectious material may enter the 

 blood-vessels, especially the veins, and be swept along with 

 the blood-current to become scattered generally throughout 

 the body. In such cases we are likely to have general or acute 

 miliary tuberculosis. Almost every organ of the human body 

 may be infected by tuberculosis. Among the most common 

 may be mentioned the lungs, the lymph-nodes, the bones, the 

 intestines, the skin, the meninges, and the serous membranes. 



Infection, as far as we know, is always to be attributed 

 directly or indirectly to some preexisting case of tuberculosis 

 in man or the lower animals. The entrance into the body is 

 most commonly by way of the lungs, where also tuberculous 

 disease is commonest in man, going by the name of consump- 

 tion. This is doubtless due to the prevalent habit of expec- 

 torating in pubHc places. Out of fifty-six samples of sputum 

 collected in street cars by Dr. W. G. Bissell, City Bacteriologist 

 in Buffalo, four were tuberculous. In forty-eight samples 

 taken from the floors of a pubHc building by Dr. C. R. Orr, of 

 the pathological laboratory of the University of Buffalo, tuber- 

 cle baciUi were found three times. According to the researches 

 of Nuttall, a person suffering from tuberculosis may expectorate 

 many millions of tubercle bacilh in the course of twenty-four 

 hours. Coughing and similar efforts may serve to disseminate 

 the bacilh (see page 152). 



Concerning the occurrence of tubercle bacilh in cow's milk 

 and butter, see pages 137 and 138. 



