230 PROTOPLASMIC ACTION AND NERVOUS ACTION 



It should be noted that in the case of some other 

 colloidal organic compounds the formation of gels may 

 be prevented instead of promoted by the addition 

 of surface-active substances; this effect was observed 

 by Schryver^ in the gelation of Na-cholate in the presence 

 of various surface-active organic compounds. He found 

 a retardation in the rate of gelation, the effect running 

 in general parallel with capillary activity and narcotic 

 action. This phenomenon is analogous to protective 

 action in colloidal precipitation. 



The protection of suspensions of lecithin against 

 precipitation by electrolytes is also an effect character- 

 istic of many surface-active compounds. Hober and 

 Gordon^ found that suspensions containing ether, chloro- 

 form, chloral, or amyl alcohol were less readily precipi- 

 tated by alkali-earth cations (Ca, Ba) than the control 

 suspensions; i.e., were stabilized; and they character- 

 ized this action as ''narcotization of the plasma mem- 

 brane colloid lecithin." Koch and MacLean^ found 

 that the stabilizing effect was not uniform with different 

 anaesthetics; some compounds so act, but others are 

 indifferent, while stiU others further precipitation, 

 especially the lower alcohols and paraldehyde, which are 

 highly water-soluble. My own observations on the 

 precipitation of lecithin by CaCla and HCl confirm this 

 result, but they show that at appropriate concentrations 

 the great majority of anaesthetics have a stabilizing 

 effect. The compounds examined included alcohols 



^ Schryver, Proceedings of the Royal Society^ By LXXXVII (1914), 

 366. 



= Hober and Gordon, Hofmeisters Beitr., V (1904), 432. 



3 Koch and McLean, Journal of Pharmacology and Experimental 

 Therapeutics, II (19 10), 249. 



