40 DYNAMICS OF LIVING MATTER 



Overton found that the alcohols, even those having large molecules, 

 could pass into the cells much more readily than the salts with smaller 

 molecules. Nernst had given another theory of semipermeability 

 which is generally accepted; namely, that the substances which go 

 through the semipermeable walls must first be dissolved in this mem- 

 brane, and that therefore such substances must be absorbed most 

 rapidly by these cells as are most soluble in the cell walls, or surface 

 films of the cells. Overton * found that plant and animal cells which 

 show the properties of semipermeability are generally most permeable 

 for those substances which are most soluble in oil or fat, e.g. alcohol, 

 ether, chloroform. He accepts Nernst's theory and draws the conclu- 

 sion that the cells, or the protoplasm of the cells, are surrounded by a 

 film of a fatty substance, such as lecithin or cholesterin, and that these 

 substances give protoplasm the quality of semipermeability. 



A similar conclusion had already been drawn by Quincke, who 

 had noticed that protoplasm assumes a spherical shape when squeezed 

 out of its cell into a watery liquid. This, he said, was only intelligible 

 when protoplasm is surrounded by a film of oil or fat.f Quincke also 

 pointed out that such films of oil must show the phenomenon of semi- 

 permeability. 



Hans Meyer and Overton J have noticed independently of each 

 other that all narcotics have one property in common; namely, a 

 comparatively great solubility in fat, or lipoids like lecithin or choles- 

 terin. The special importance of this lies in the fact that the narcotic 

 effect of a substance increases, on the whole, with the degree of its 

 solubility in fat. They are inclined to believe that the chemical nature 

 of the narcotic is otherwise of no or only minor importance, as they 

 find that chemically inactive bodies may be very powerful narcotics, 

 if only their solubility in oil is comparatively high. It seems to me, 

 however, that in view of the presence of so many enzymes in our cells, 

 substances may be very active in our body, which in the absence of such 

 enzymes may appear rather inert. This does not, however, contradict 

 the fact that the solubility of narcotics in fat plays a role in the absorp- 

 tion of narcotics. Those cells in our body which are richest in lipoids, 

 namely, the ganglionic cells, also feel first the effects of narcotics. 



Meyer and Overton assume that the narcotics, such as alcohol, 

 ether, etc., act merely by altering the physical properties of the cells 

 in whose lipoids they dissolve. The fact that anaesthetics like ether 

 and chloroform dissolve fat was utilized for an explanation of their 



* Overton, Vierteljahreschrift der naturforschenden Gesellsch. in Zurich, Vol. 44, p. 88, 

 1899. (The original was not accessible to me.) 



t Quincke, Sitzuugsberichte der Berliner Akademie der Wisscnschaften, p. 791, 1888. 

 J Overton, Studien uber die Narcose, Jena, 1901. 



