354 B A CTEEIOL OGY. 



into the air-passages, and by inoculation into the ante- 

 rior chamber of the eye. 



In the human subject the most common portals of 

 infection are, doubtless, the air-passages, the alimentary 

 tract, and cutaneous wounds. When introduced subcu- 

 taneously the resulting process finds its most pronounced 

 expression in the lymphatic system. The growing 

 bacilli make their way into the lymphatic spaces of 

 the loose cellular tissue, are taken up in the lymph- 

 stream and deposited in the neighboring lymphatic 

 glands. Here they may remain and give rise to no 

 alteration other than that seen in the glands them- 

 selves ; or they may pass on to neighboring glands, 

 and eventually be disseminated throughout the lym- 

 phatic system, ultimately reaching the vascular system. 



Having gained access to the bloodvessels the results 

 are the same as those following intravascular injection 

 of the bacilli, namely : general tuberculosis quickly 

 follows, with the production of miliary tubercles most 

 conspicuous in the lungs and kidneys ; less numerous 

 in the spleen, liver, and bone-marrow. 



When inhaled into the lungs, if conditions are favor- 

 able, multiplication of the bacilli quickly follows. Co- 

 incident with their growth they are mechanically pressed 

 into the tissues of the lungs. As multiplication con- 

 tinues some are transported from the primary site of 

 infection to healthy portions of the lung-tissue, where, 

 through their development, the process is repeated. 



In the same way infection by way of the alimentary 

 tract is in the main due to the bacilli being forced by 

 mechanical pressure into the walls of the intestines. In- 

 vestigation has shown that lesions of the intestinal coats 

 are not necessary for the entrance of tubercle bacilli 



