CHEMICAL PHENOMENA IN LIFE 



that the plasmolytic power of a certain solution 

 proves distinctly that the substance cannot pass 

 through the living protoplasmatic membrane. 

 If the solution does not effect any plasmolysis, 

 we may be sure that the substance enters the cell 

 more or less considerably. 



Ernest Overton was the first who thoroughly 

 investigated these interesting problems in 1895. 

 He found that mon-acid alcohols, aldehydes, 

 and ketones, also esters of fatty acids and 

 alkaloids, produce least plasmolysis. As a rule 

 it is impossible to bring about plasmolysis by 

 means of these substances. They enter the cell 

 very easily and pass through the plasmatic 

 membrane without any difficulty. Glycols and 

 amino-compounds cause plasmolysis a little more 

 readily. With glycerin or erythrite it is still 

 easier to bring about plasmolysis. But the sugars 

 and the substances most closely related (for 

 instance, mannite), the amino-acids and the salts 

 of organic acids very readily produce plasmolysis. 

 They cannot pass through the protoplasmatic 

 membrane but with great difficulty. Finally, the 

 salts of inorganic substances very quickly cause 

 plasmolysis, since they very slowly pass the 

 plasmatic membrane, or practically do not pass 

 the boundary of protoplasm. Overton added to his 

 valuable experiments a most ingenious conclusion. 

 He drew attention to the fact that just such 

 substances easily pass through the protoplasmatic 



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