252 IRRITABILITY 



of suppression of the oxydative processes. Indeed, the disap- 

 pearance of the perceptible vital activities, the decrease of 

 irritability, the restriction of the conduction of excitation, the con- 

 tinuance of an anoxydative breaking down, the recovery on ces- 

 sation of narcosis, provided oxygen is present, etc., in short, all 

 the characteristics of narcosis so far known must be expected 

 and demanded if a suppression of the oxydative processes exists 

 during narcosis. 



There is only one point which at the first glance would not 

 seem to agree entirely with the assumption. This is the fact that 

 depression sets in with a relatively greater rapidity in narcosis 

 than when the supply of oxygen is completely withdrawn. 

 Depression of the centers in the spinal cord, which begins in 

 about five to ten minutes after artificial circulation of an oxygen- 

 free, alcohol-containing, saline solution, is not brought about for 

 more than an hour when the same saline solution but without 

 alcohol is introduced. This difference is still more strikingly 

 apparent in the nerve. The same degree of depression, which is 

 produced in the nerve in a nitrogen-ether mixture within about 

 five minutes, is not reached in pure nitrogen without ether until 

 after the lapse of from two to four hours. In order to investi- 

 gate this relation somewhat more closely I have questioned if it 

 is possible for a living system, which has been narcotized to a 

 certain extent, to regain its irritability in a completely oxygen- 

 free medium, if cessation of the narcosis takes place after a 

 period essentially shorter than the time of asphyxiation of the 

 system under equal conditions. If the depression of narcosis is 

 founded exclusively on asphyxiation, it would be expected that 

 no recovery could occur. Experiments which I have made on 

 the spinal cord centers as well as on the peripheral nerves have, 

 however, demonstrated exactly the contrary. If a frog is 

 subjected to an artificial circulation of an oxygen-free saline 

 solution containing 5 per cent, of alcohol until reaction is lost, 

 being certain of this by the injection of a weak dose of strych- 

 nine, and if now a cessation of the narcosis is brought about by 

 the transfusion of oxygen-free saline solution, the centers of the 

 animal recover completely within ten to fifteen minutes, as shown 



