404 



CRILE— PHYSICAL STATE OF 



[April i8, 



long-continued insomnia permanently destroys a part of the brain 

 cells just as do too great physical exertion, certain drugs, emotional 

 strain, exophthalmic goitre or hemorrhage. We found, however, 

 that if instead of natural sleep the rabbits were placed for the same 

 number of hours under nitrous oxide anesthesia, not only were 

 the brain cells prevented from physical deterioration, but that 90 

 per cent, of them became hyperchromatic. This gives us a possible 

 clue to the actual chemical effect of sleep. For since nitrous oxide 

 owes its anesthetic effect to its influence upon oxidation, we may 







Fig. 6. Area from cerebellum, woodchuck, hibernating. 



infer that sleep also is a question of oxidation of the cell content. 

 If this is true, then it is probable that inhalation anesthetics exert 

 their peculiar influence upon that portion of the brain through which 

 sleep itself is produced. If nitrous oxide anesthesia and sleep are 

 chemically identical, then we have a further clue to one of the pri- 

 mary mechanisms of life itself; and as a practical corollary one 

 might be able to produce artificial sleep very closely resembling 

 normal sleep, and with this advantage, — that by using an anesthetic 

 interfering with oxidation the brain cells might be reconstructed 

 after physical fatigue, after emotional strain, or after the depression 

 of disease. 



In the case of the rabbit in which nitrous oxide was substituted 

 for sleep the appearance of the brain cells resembled those in but 

 one other group experimentally examined, — the hibernating w^ood- 

 chucks. 



