II 



3). Hiumolytic experiments in the living organism 

 and in test-tubes (normal lysins; - - lysins pro- 

 duced by immunising; --bacterial lysins; --im- 

 mune body and complement). 



Of the other experiments undertaken at our course, 

 I might point out the following: 



1. Observation of regeneration of tissues in vivo [tad- 

 pole's tail]. 



2. Production of various degenerations. 



3. Experiments on irritability of monocellular orga- 

 nisms (chemotaxis, electrotaxis, geotaxis etc.). 



It is easily seen, that all these three courses point 

 in the same direction, towards comparative pathology. 



It is now, no doubt, generally accepted that compa- 

 rative pathology, in the widest sense of the word, is 

 the end of all pathological research, but its great im- 

 portance has not been recognised till since the 

 middle of the nineteenth century. Heusinger then fore- 

 told that we were standing ,,a la veille de la creation 

 d'une pathologic comparee", but his learned Reche.rchcs 

 de pathologic comparee 1844 were written more from 

 a veterinary and epidemiological than from a general 

 pathological point of view. Heusinger, anyhow, did not 

 seem to have such a clear grasp of the aim and impor- 

 tance of comparative pathology as Fenger, who already 

 in the previous year had treated the same subject with 

 a masterly hand in a short paper written when compet- 

 ing for the post of medical lecturer 7 ). Fenger here 

 deals at great length with the question of how to ex- 

 plain the low standard of comparative pathology, and de- 

 mands that it shall be able ,,to show the evolution of 

 the pathological idea through the animal kingdom." 



