13 



young and () hi animals. Growth accelerating and inlii- 

 hiting I'aclors of serum. Action ol' heterogenic sera on 

 rii)rol)iasts. I'hysico-cliemical i)roperlies of sera from 

 }-oung and old animals. Action of shaken serum on 

 filH'oblasts. The rate of growth of fibrol)lasts in long 

 periods of time in condition of uninterrupted life. 

 The inherent growth energy of tissues. The residual 

 energy of tissues, i he nutrition of the tissue cells in 

 vitro. Action of heterologous tissue extract on tissue 

 cells. Leucocytic trephones. The ability of leucocytes 

 to synthesise from the serum constituents, the growth 

 promoting substances for fibroblasts. 



2) T h e physiological integrity of tissue 

 cells 155 



General Growth of independent cell individuals 

 or growth of tissue? Method for isolation of single 

 tissue cells. The growth of scattered tissue cells 

 in cultures. Explanations of the missing growth of 

 single individuals of tissue cells. The anastomotics 

 between the cell individuals in tissue cultures. The 

 significance of the intercellular protoplasma bridges. 

 The controlled cell division. Rythmics of cell divisions 

 in cultures of fibroblasts. Methods of investigation. 

 Serial photography of tissue cells in cultures. The 

 average duration of life of the fibroblasts under the 

 experimental conditions. Discussion. The physiological 

 integrity of the contractile elements in embryonic 

 heart tissue. ■ Technique of investigation. Action of 

 fragments of heart from the same heart. Action of 

 the same species. Action of fragments of heart from 

 different species. 



3) Interactions of the various tissue cells 



in vitro 188 



Growth o'f complex tissues. Transplantion. The 

 atreptic theory of E h r 1 i c h. Interaction of epi- 

 thelium and fibroblasts. The question of dedifferen- 

 tiation. Controlled growth. Technique. The effect of 

 the plasma on the stroma of the intestinal organism. 

 Regeneration. Cicatrization. Transplantation. Milieu 

 i n t e r i e u r 8. 



