Guilliermond - Atkinson — 36 — Cytoplasm 



think that the properties of protoplasm are determined by the pro- 

 portions of its fundamental constituents. These are not distributed 

 in a hit-or-miss fashion, but are always found for the same type 

 of cell in invariable ratios which Mayer and Schaeffer call cellu- 

 lar constants. 



It is thus that the fatty acid content is very variable from one 

 species to the next but for all tissues of a single species it always 

 fluctuates about a constant value. 



In the matter of cholesterol, the content differs very greatly 

 from one organ to another in the same species but is rather con- 

 stant for a given organ no matter what the species. It is charac- 

 teristic of the organ under consideration. The ratio, cholesterol : 

 fatty acid, or the lipocytic coefficient, is characteristic of a given 

 species. It constitutes a cellular constant. There exists also a 

 mineral constant. Similarly the water content for each type of 

 tissue always fluctuates about the same value, therefore each type 

 of tissue in a species possesses a constant and specific content of 

 water of imbibition. Water is thus a cellular constant. The 

 research of Nicolle and Alilaire brings out similar results 

 for bacteria. Thus in a typhus bacillus there is found 85% of 

 water whereas in an anthrax bacillus there is only 75%. 



The 2?H value, the isoelectric point of cytoplasmic colloids, and 

 the rH, the oxidation-reduction potential of cytoplasm, appear also 

 to be cellular constants. 



Mayer and Schaeffer have shown, furthermore, that there 

 exists for each type of cell a constant ratio in the proportions of 

 these different constants. Thus a close relationship is observed 

 between the ratio of cholesterol : fatty acid, or lipocytic coefficient, 

 and the imbibition of water by cells, the higher the coefl^cient, the 

 more water imbibed by the cells. The lipocytic ratio is thus an 

 index of a cellular property. 



This relation between lipocytic coefficient and the water con- 

 tent of a cell is explained in the following manner : cholesterol, as 

 has been said, has the property of absorbing a rather large quan- 

 tity of water by imbibition. The combined fatty acids, on the con- 

 trary, do not imbibe water. But for some time it has been shown 

 that cholesterol and fatty acid compounds are soluble one in the 

 other and this mixture becomes penetrable to water. Thus, the 

 more cholesterol there is contained in a protein gel or coacervate, 

 the more water there will be imbibed. 



The outcome of this research is that the cells of organisms do 

 not show their known properties to the same degree. They have 

 general properties which are encountered in all cells (protoplasmic 

 properties) and properties which are related to the function which 

 they perform in the cell. The general properties depend upon con- 

 stituents whose value appears constant for each cellular type. 



Ionic reaction of cytoplasm:- Unfortunately, in spite of their pre- 

 cision, the methods for measuring pB. are not easily applicable 

 to living cells. What is needed, if it were possible, is a method for 



