LIPOID-ALTERANT SUBSTANCES 189 



The most remarkable general physiological effect 

 produced by the lipoid-alterant substances is a reversible 

 suppression of irritability or spontaneous activity. 

 This effect always appears in certain definite, not too 

 high, concentrations of these compounds, and constitutes 

 the phenomenon of narcosis or anaesthesia, which is 

 universal in living matter.^ The power of inducing 

 this state seems to be independent of the special chemical 

 nature of the narcotizing compound; evidently this 

 power is connected in some manner with the general 

 physical properties just named; and the question first 

 arises whether the lipoid-solubility of these compounds 

 or their surface-activity is the property primarily 

 responsible for this characteristic action. 



CORRELATION BETWEEN PHYSIOLOGICAL ACTION AND 



LIPOID-SOLUBILITY 



The existence of a relation between the solubility of 

 chemical compounds in fats and their narcotic action 

 was early noted, first by Bibra and Harless in 1847, ^^^ 

 later by Claude Bernard, Hermann, Richet, Ehrlich, 

 and others.^ Richet propounded the rule that any 

 narcotizing compound has the stronger action as a 

 narcotic the lower its solubility in water. This is 

 similar to the rule of Overton and^ Meyer that the 

 narcotic effectiveness of a compound runs parallel with 



^"We may say that everything living is sensitive and can be 

 anaesthetized; whatever is not sensitive is not living and cannot be 

 anaesthetized." — Claude Bernard, address, "La Sensibilite" (delivered 

 in 1876), published in his book. La Science Experimentale, Paris (1890). 



^ Cf. Overton, Studien iiber die Narkose, Jena (i 901), for a historical 

 account of the earlier work on narcosis. 



