40 LOCALIZATION OF MICRO-OKG ANISMS . 



tion of a pure culture into the trachea. 2. Injection through a 

 tracheal tube. In the latter case the injection was not made until 

 the tracheal wound had completely healed around the canula, and 

 the tube was left in situ until the death of the animal. The tra- 

 cheal wound in these cases never became infected. Direct injections 

 into the trachea always produced positive results, the animals 

 dying of anthrax in from forty to forty-eight hours. As in these 

 instances the tracheal wound always became infected, it became 

 necessary to kill the animals soon after the injection in order to 

 determine the effect of the bacilli on the pulmonary tissues. On 

 microscopical examination of the specimens of animals killed 

 sixteen hours after direct injection, free bacilli were found in the 

 wound, the walls of the alveoli, in the juice canals and only 

 a few rods in the interior of the alveoli themselves and the 

 lumen of the bronchial tubes. The bacilli were most abundant 

 in the so-called dust cells, derivatives of the alveolar epithelia. 

 No bacilli could be seen in the peri-bronchial and peri-vascular 

 lymph spaces. On examination of the bronchial glands, a very 

 peculiar arrangement of the bacilli was found. Each section con- 

 tained countless bacilli which occupied almost exclusively the 

 lymph channels of these organs ; in the bloodvessels they were 

 scanty. The bacilli and threads surrounded the periphery of the 

 cortical follicles in the shape of a very dense zone, the density of 

 which diminished toward the centre of the follicle and followed 

 the medullary strings. In animals killed seventeen hours after 

 direct injection, small pieces of the lung or liver planted on a 

 proper culture-soil were soon surrounded by a copious growth of 

 bacilli. In animals injected through a canula after complete cica- 

 trization of the tracheotomy wound, killed after forty hours, the 

 bacilli were found most numerous in the pulmonary bloodvessels, 

 while the dust cells contained only a single rod, if any. Most all 

 of the bacilli had left the lymphatic glands, and had passed into 

 the general circulation. From these experiments the author con- 

 cluded that the bacilli of anthrax can enter the circulation through 

 the mucous membrane of the bronchial tubes, and that the juice 

 canals, lymphatic channels of the bronchial tubes, lungs, and the 

 bronchial glands are the channels through which infection takes 

 place. The carriers, which are directly concerned in the transpor- 

 tation of the bacilli from the mucous surface into the lymphatic 

 system, are yet to be discovered. It seemed strange to the author 

 that no bacilli could be found in leucocytes, but always only in 

 epithelial cells. Final localization of the bacilli of anthrax 

 which have entered the circulation through the lungs takes place 

 in distant organs through the medium of the general circulation 

 by implantation upon the endothelial lining of the capillary ves- 



