Chapter XX — 223 — Summary and Conclusions 



Unfortunately, the very precise knowledge which we possess 

 at the present time on the constitution of the cytoplasm consists 

 almost exclusively of morphological facts. We still know only 

 very little about the role of the different elements which compose 

 this structure. We know that the plastids play an important part 

 in the phenomena of photosynthesis and in amylogenesis and that 

 the vacuoles play a part in the osmotic phenomena of the cell. Our 

 knowledge ceases here. But, as Claude Bernard says, "Anatomy 

 would have no reason for being if it did not have a physiological 

 base." 



It is, however, very important to know and to understand this 

 morphological structure, for, just as WuRMSER wrote, "It is cer- 

 tain that a chemical system composed of a number of bodies will 

 develop differently according to w^hether these parts are all mingled 

 and thus destined to act mutually or whether, on the contrary, they 

 are distributed as independent groups." Therefore the entire prob- 

 lem will consist, from now on, in seeking the relationship between 

 morphological structure and the physiological activity of the cell. 

 The realization of this problem must be hoped for in the progress 

 of physical chemistry. "From now on", as Friedl Weber says, 

 "the cytologist must become both physicist and chemist". We are 

 constrained, however, to add that the cytologist must at the same 

 time remain a morphologist. 



