110 PATHOLOGY. 



into which Loth the bacilli and the chain-like micrococci have 

 been introduced. In the former the cellular tissue is full 

 of red corpuscles and lymph cells, so that the bacilli can 

 often be recognised only with great difficulty among the 

 numerous cell nuclei. The other ear presents totally different 

 appearances. Spreading from the place of inoculation, one 

 can see extremely delicate and regular micrococcus chains, here 

 l^ressed together so as to form thick masses, traceable almost to 

 the base of the ear, all the tissues of the part occupied by them 

 being remarkably altered. As far as the micrococci extend, 

 neither red blood globules nor nuclei of lymph or of connective 

 tissue cells can be seen. Even the extremely resistant cartilage 

 cells, and the plasma cells so richly present in the mouse's ear, 

 and which are likewise characterised by great resisting power, 

 are pale and scarcely recognisable. All the constituents of the 

 tissue look as if they had been treated with caustic potash ; they 

 are dead, they have become gangrenous. Under these circum- 

 stances the bacteria develop all the more vigorously, and the 

 micrococci penetrate in numbers into the damaged blood and 

 lymphatic vessels, and here and there they fill them so com- 

 pletely that the vessels aj)pear as if injected. Among these 

 the septicemic bacilli, no longer obscured by nuclei, are seen 

 very distinctly in small groups, which are at times very dense, 

 and can be traced up to the root of the ear, and indeed be- 

 yond it, having at the same time increased enormously in 

 tlie blood, and ultimately causing the death of the animals. 

 The micrococci, on the other hand, and the destructive process 

 associated with them, have only extended during the same time 

 (about fifty hours) as far as the vicinity of the root of the ear, 

 where their limit is sharply defined. The appearances presented 

 b}' the ear on o, post mortem examination lead to the conclusion 

 that the action of these micrococci in causing gangrene is 

 somewhat as follows : — Introduced by inoculation into living 

 animal tissues, they multiply, and as a part of their vegetative 

 process they excrete soluble substances, which get into the 

 surrounding tissues by diffusion. When greatly concentrated, 

 as in the neighbourhood of the micrococci, this product of 

 the organisms has such a deleterious action on the tissue 

 cells that they perish and finally completely disappear. At a 



