74 EXPERIMENTAL RESEARCHES 



entirety present the appearance of a haemor- 

 rhagic tumour. This angiotactic attraction of 

 the blood-vessels is an essential condition for 

 the growth of the tumours ; for if, as is the case 

 in intra-peritoneal inoculation, these angiotactic 

 properties cannot become active, or if they have 

 been lost, as is the case in immunised animals, 

 proliferation remains very limited both as 

 regards its duration and its extent, and it 

 rapidly ceases whilst the whole tissue becomes 

 necrotic. 



As you see, I have dealt with a number of 

 apparently very different subjects of biology and 

 pathology, which are, however, united by a 

 common bond. We have before us the com- 

 petition of the different individualities for their 

 nutrient materials. The majority of such 

 chemical compounds are organically bound 

 within the cell to its constituents. This is, I 

 think, especially true of the lipoid bodies, like 

 fat, lecithin and others. In this respect I may, 

 perhaps, remind you that normal tissue, e.g., 

 the cortex of the kidney, contains fat in such a 

 hidden modification, since it shows fat granules 

 neither microscopically nor by the osmic acid 

 reaction. If one examines a similar organ in 

 the stage of fatty degeneration, it shows macro- 



