THE PROCESSES OF DEPRESSION 247 



at once. During narcosis, therefore, the centers, in spite of their 

 great requirement of oxygen, lose their capability of oxydative 

 splitting up and consumption of oxygen. 



After the methods for asphyxiation of the nerve had been 

 worked out and perfected the wish arose likewise to carry out 

 for these structures an analogous series of experiments to that 

 employed for the centers and based on the same chain of reason- 

 ing. These investigations have the advantage of essentially 

 simpler conditions. After having convinced myself by experi- 

 ments, that the results on the nerve were in complete conformity 

 with those on the spinal cord, at my suggestion Frohlich 1 repeated 

 and continued these experiments on a more extended scale. 

 A nerve was asphyxiated by the previously described method. 

 This is accomplished in the simplest manner by the opening 

 or closing of stop cocks in the apparatus I have employed 

 which permit of pure nitrogen, or nitrogen with ether, and finally 

 also oxygen with ether or pure oxygen being conducted at will 

 through the glass chamber. If the nerve was so far depressed 

 in pure nitrogen that conductivity became obliterated for about 

 two cm. of the asphyxiated stretch, it was then narcotized in 

 nitrogen. Following this oxygen with ether was supplied for a 

 time. Then the oxygen-ether mixture was displaced by one of 

 nitrogen and ether and finally by pure nitrogen. Even after a 

 prolonged period, a recovery in pure nitrogen never took place. 

 On the other hand, the nerve recovered at once, as soon as oxygen 

 without ether was introduced. The results of these investigations 

 are, therefore, completely in harmony with those undertaken by 

 Winterstein on the nervous centers. They were later likewise 

 entirely confirmed by similar experiments of Heaton. 2 All these 

 investigations furnished the proof that in narcosis, living sub- 

 stance, notwithstanding even the greatest oxygen deficiency, is 

 not capable of producing oxydation, neither can consumption of 

 oxygen take place, with which, after cessation of the narcosis, 

 oxydative splitting up can be carried out. 



1 Fr. W. Frohlich: "Zur Kenntniss der Narkose des Nerven." Zeitschr. f. allgem. 

 Physiol. Bd. Ill, 1904. 



2 Trevor B. Heaton : "Zur Kenntniss der Narkose." Zeitschr. f. allgem. Physiol. 

 Bo. 1910. 



