1912.] Examining Normal and Diseased Tissues. 153 



(4) Diseased Tissties (Mice and Bats), 

 (a) Healing of wounds. 

 (&) Trichinosis. 



(c) Experimental tuberculosis. 



(d) Toxic degeneration of the liver. 



(e) Malignant growths. 



(a) In the healing of wounds produced in the skin, liver, and kidney, the 

 pyrrhol cell appears on the scene after the initial emigration of leucocytes 

 from the dilated blood-vessels has taken place. The extravasated leucocyte 

 shows glycogen and fat granules in its protoplasm. The pyrrhol cell 

 phagocytes such leucocytes or incorporates either glycogen or fat granules 

 derived from leucocytic degeneration. Eventually it stretches into the 

 spindle cell of the young connective tissue, losing consecutively both its 

 affinity for the vital and fat stains. In skin wounds the pyrrhol cell is derived 

 from the subcutaneous tissue, whereas in liver and kidney wounds I have 

 been able by means of the vital stain to demonstrate the migration of 

 pyrrhol cells from the serous coat of the injured organ or from the peritoneal 

 cavity into the wounded area. 



(6) The activity of the pyrrhol cell is most prominently displayed in the 

 surroundings of parasites, such as the trichina and other worms. In the case 

 of the trichina the " pole cells " of the muscular " spindles " accept the vital 

 stain. It appears that in wandering towards the trichina the pyrrhol cell 

 passes through lymphatic glands, whose marginal sinuses and lymphatic spaces 

 in general abound with vitally stained cells of the pyrrhol type. These cells 

 first spread into the interstitial muscular tissue and thence penetrate the 

 sarcolemma, arranging themselves on the outer surface of the encapsuled 

 parasite. Purely mechanical conditions are responsible for the typical 

 arrangement of the pole cells at the extremities of the " trichina spindle." 



(c) Tuberculosis. — I have established a fundamental difference in the 

 distribution of avian and bovine bacilli of tuberculosis, when grafted into the 

 peritoneal cavity of the mouse. Hitherto, in all cases of spontaneous tuber- 

 culosis in the mouse, the " avian " bacillus has been found. Koch had already 

 drawn our attention to the chronic course of tuberculosis in the mouse. And 

 yet, when the mouse is subjected to an injection with bovine or human 

 tuberculosis, either through the blood-vessels or the peritoneal cavity, the 

 disease runs a comparatively rapid course, in many cases assuming a form of 

 bacillary septicaemia or miliary tuberculosis of the lung. In accordance with 

 these facts I am able to show that after peritoneal injection of bovine 

 material, besides rapidly caseating tuberculosis of the peritoneum, the chief 



