346 BACTERIOLOGY. 



from the lumen of the intestines into the internal 

 organs and tissues. They may be transported from 

 the intestinal tract into the lymphatics in the same 

 way that the fat-droplets of the chyle find entrance into 

 the lymphatic circulation. 



They may gain access to the tissues by way of the 

 tonsils. 



Unlike most pathogenic organisms, the tubercle bacil- 

 lus is resistant to drying. When thrown off from the 

 lungs in the sputum of tuberculous patients, unless spe- 

 cial precautions be taken to prevent it, the sputum be- 

 comes dried, is ground into dust, and sets free in the 

 atmosphere the tubercle bacilli which came with it 

 from the lungs, and which have the property of 

 exciting the disease in susceptible persons who inhale 

 them. The frequency of pulmonary tuberculosis points 

 to this as one of the commonest sources and modes of 

 infection in human beings. This opinion is borne out 

 by statistical studies upon the disease, as well as by such 

 evidence as Cornet 1 has produced upon the infective 

 nature of dust taken from apartments occupied by per- 

 sons suffering from pulmonary tuberculosis. 



LOCATION OF THE BACILLI IN THE TISSUES. The 

 bacilli will be found most numerous in those tissues 

 which are the seats of the active stage of the process. 



In the initial stage of the disease the bacilli will 

 be fewer in number than later. At this time only 

 single rods may here and there be found ; later they 

 are more numerous ; and, finally, when the process 

 has advanced to a stage easily recognizable by the naked 

 eye, they are found in the granulation-zones in clumps 

 and scattered about in large numbers. 



i Cornet: Zeitschlft fur Hygiene, 1889, Bd. v. S. 191. 



