246 ANNALS OK THE MISSOURI BOTANICAL GARDEN 



[Vol. 2 



solvents. Overton considered the endosmosis of dissolved 

 substances into living cells as merely a question of solubility. 

 It is known how fertile this idea has proved in physiology, 

 particularly in the phenomenon of narcosis, where it is still 

 the leading hypothesis in animal physiology. 



But recently experimental work, including my own, has 

 shown that it is scarcely quite correct to consider the endos- 

 mosis of solutions into living cells as a typical solution 

 phenomenon. According to Loewe even the partition of 

 methylene-blue or of chloroform between oil and water cannot 

 readily be explained by means of the principle of Henry and 

 Berthelot. Bather, the oily solution of such substances is 

 not a true solution, but only a colloidal solution; so it is not 

 ruled by the laws of osmotic pressure, but by the laws of 



adsorption. 



A striking fact was discovered by Traube and by myself 

 in studying the effects of alcohols and other capillary-active 

 substances on living cells. Their injurious action clearly and 

 exclusively depends upon the relative capillary activity. 

 Every one of these substances kills the cells at a concentration 

 corresponding exactly to a certain value of surface tension. 

 The main importance of this observation consists in the evi- 

 dence that in narcotic effects capillary phenomena must be a 

 dominant factor. This cannot be interpreted by the supposi- 

 tion that the entrance of narcotics into cells is due to true 

 solution phenomena. The observed capillary effects distinctly 

 show that the factor of real moment is to be found in altera- 

 tions of contact-surface ; but such surface-phenomena are met 

 with only in colloids and in their adsorption. 



A prominent feature of our experiments involves the fact 

 that cells of higher plants are constantly killed by concentra- 

 tions of narcotics such that the capillary activity reaches about 

 two-thirds of the surface tension of pure water in contact with 

 air. It is remarkable that saturated and neutral emulsions of 

 triolein or other typical fats always show approximately the 

 same surface tension value. This result I tried to explain 

 by means of the hypothesis enunciated in the following 

 sentences: Alcohol and other narcotics are taken up by ad- 



