1 9 1 9] HAA S~RESPIRA TION 379 



asphyxiation. His h^'pothesis maintains that the absorption of 

 oxygen is not reduced during narcosis, but that the oxygen is 

 prevented from going to its usual point of attack. This would 

 necessitate the assumption that oxygen is more readily absorbed 

 by the lipoids than by the other substances of the cell, which is not 

 the case. An objection to all theories which make narcosis con- 

 ditional on lipoid solubility is the fact that magnesium sulphate 

 and carbon dioxide, which are not soluble in lipoid, produce typical 

 anesthesia. 



HoBER (10) has formulated the h\^othesis that narcosis is due 

 to inhibition of enzymatic processes, brought about by a decrease 

 in dispersion. This hypothesis is favored by the investigations of 

 Batelli and Stern (2), who found that proteins, such as the 

 nucleo-proteins, are influenced by narcotics in approximately 

 the same relative and absolute concentrations as those at which the 

 enzymes are affected. In this connection Vernon (28) found that 

 most narcotics are harmless to oxidases up to a definite limiting 

 concentration, beyond which injury occurs. Hober explains the 

 retardation or inhibition of enzyme action as due to the fact that 

 narcotics go into the surface between the enzymes and the medium 

 in which they are dispersed, thereby displacing the substratum on 

 which the enzymes act. 



The investigations hitherto discussed are largely based on 

 measurements of the absorption of oxygen. In many cases such 

 measurements could be made more accurately than determinations 

 of the amount of carbon dioxide produced. Since the writer has 

 recently been able to develop a method for the measurement of 

 minute amounts of carbon dioxide in solution, it seemed to him that 

 a fresh investigation of the subject by means of this method was 

 desirable. 



Previous investigations on the effect of narcotics on the produc- 

 tion of carbon dioxide have yielded somewhat contradictory 

 results. Appleman (i) found that vapor of ethyl bromide approxi- 

 mately doubles the respiration of potatoes. Mayer (18) found 

 that 0.25 per cent prussic acid stops the respiration of higher plants 

 entirely. Schroeder (24) observed a decrease in respiration when 

 Aspergillus was treated with ether. He found that prussic acid 



