460 NERVOUS SYSTEM. 



that the subject of the observation, awake, but in a condition 

 of complete repose, appropriated sixty-seven per cent, of 

 the entire amount of oxygen of the twenty-four hours dur- 

 ing the night, and thirty-three per cent, during the day, 

 while he eliminated fifty-eight per cent, of the entire amount 

 of carbonic acid excreted, during the day, and forty-two per 

 cent, during the night. When the subject of the experi- 

 ment worked during the day, by turning a heavy wheel, 

 the appropriation of oxygen was thirty-one per cent, for the 

 day, and sixty-nine per cent, for the night ; the elimination 

 of carbonic acid was sixty-nine per cent, for the day, and 

 thirty-one per cent, for the night. According to these ob- 

 servations, the system stores up oxygen at night for use 

 during the day, at this time eliminating a relatively small 

 quantity of carbonic acid ; and, during the day, excretes 

 more carbonic acid than during sleep, appropriating then a 

 relatively small amount of oxygen. 1 



This theory of sleep seems to rest upon observations too 

 restricted to be adopted without reserve. It is stated, in- 

 deed, that the first experiments of Pettenkofer and Yoit 

 were not confirmed in other observations made upon the 

 same person. a It is hardly possible, with our present infor- 



1 PETTENKOFER UNO VOIT, Ueber Kohlensdureausscheidung und Sauerstoff- 

 aufnahme wahrend des Wachens und Schlafens beim Menschen. Annalen der 

 Chemie und Pharmacie, Leipzig und Heidelberg, 186*7, Bd. cxli., S. 300, 303. 



2 Journal of Anatomy and Physiology, Cambridge and London, 1868, vol. ii., 

 p. 181. 



The statement alluded to above is to be found in the report on physiology, 

 by Drs. Rutherford, Gamgee, and Frazer (loc. cit.\ but there is no indication 

 where the new observations of Pettenkofer and Voit were published. We find 

 no allusion to any experiments later than those published in 1867 in the Anna- 

 len dcr Chemie und Pharmacie, in Schmidts Jahrbiicher, from that date to the 

 present time. In an article by these authors on the excretions, etc., observed 

 in a patient affected with leucocythemia, it appears that the smallest difference 

 in the appropriation of oxygen during the day and at night, in a heakhy person, 

 was fifty-one per cent, for the day, and forty-nine per cent, at night, which is 

 so slight a variation, that it may practically be disregarded. (PETTENKOFER UND 

 VOIT, Ueber den Stojfverbrauch bei einem leukdmischsn Manne. Zeitschrift fur 

 Biologic, Munchen, 1869, Bd. v., S. 327.) 



