TOXICOLOGY AND PHARMACOLOGY 389 



The action of narcotics on the permeability of electrolytes is 

 reversible according to R. HOBER, and may be reversed by washing 

 them out provided the amount of added narcotic is not too great. 

 R. HOBER is of the opinion that narcosis is characterized by a change 

 in the plasma pellicle in which the increase of permeability to normal 

 stimuli is inhibited. 



A physico-chemical study by S. LOEWE actually showed that 

 chloroform was adsorbed by the white matter of the brain and that 

 sulphonal, trional and tetronal were adsorbed by lipoids. 



We see from the table that, at first, chloroform disappears very 

 rapidly but that the final portions are tenaciously held. A similar 

 table for ether reveals an approximately proportional disappearance 

 of ether from the blood in given units of time, which would approxi- 

 mately answer the demands of HENRY'S law. The slower recovery 

 from chloroform than from ether narcosis is thus explained. 



It is evident from what has been previously said that narcosis 

 merely represents a given segment of the curve which different con- 

 centrations of the narcotic cause in the turgor of the cell lipoids. 

 The commencement of the curve with low narcotic concentration 

 indicates the condition of irritability before narcosis, the terminal 

 limb with high narcotic concentration means death. 



What has been said here of benumbing the entire body mutatis 

 mutandis, applies, for the individual organs, in the case of local anes- 

 thesia. Local anesthesia may be produced by all sorts of substances 

 by very dilute caustics (acids, phenol), by distilled water, by aniso- 

 tonic salt solutions, in short, by all substances which change the 

 turgor of the cell lipoids. Practically most of them are useless be- 

 cause the first portion of the curve, the state of irritation which is 

 expressed by pain in subcutaneous injections, is too prolonged; in the 

 case of others, because the segment which signifies local anesthesia and 

 which lies between the "irritation limb" and that of permanent 

 damage is too short; still in others, because an irreversible change in 

 the cell colloids may occur even with the smallest doses, or other cell 

 colloids suffer too much in sympathy. Practically only such anes- 

 thetics are utilizable as produce only a reversible change in the turgor 

 of the nerve lipoids, as is exemplified by cocain, novocain and 

 anesthesin. 



It is not difficult to range the other methods of anesthesia, such 

 as cold and the production of anemia in this scheme, but experimental 

 confirmation is still lacking. 



Colloid research also offers an explanation of certain by-effects of 

 narcotics. [EVARTS A. GRAHAM has shown that the toxic action of 

 many anesthetics is due in part to mineral acids formed by their 



