THE VARIATIONS DURING LIFE 127 



Nagai have shown, however, that the increases in body weight, which 

 are only occasionally observed in the sleeping animals during periods 

 of comparatively short duration, must in all probability be ascribed to 

 condensation of water vapour. Nagai makes the following calculation 

 of the quantity of oxygen stored according to Regnault and Reiset's 

 hypothesis in one of their experiments. They found an oxygen 

 absorption of 28 c.c. per kg. and hour and an elimination of carbon 

 dioxide of IIT c.c. (R.Q. = 0-4). As about 16 c.c. oxygen would 

 be used up in catabolizing the quantity of fat corresponding to n-i 

 c.c. CO 2 , 12 c.c. oxygen should have been stored per kg. and hour. 

 In 30 days, which is a common duration for a period of sleep, this 

 would have amounted to 8640 c.c. and the animal should be able to 

 live on for 3 weeks more in an oxygen-free atmosphere. It can live at 

 most for 4 hours, and this power of enduring oxygen want does not 

 therefore afford any real support to the hypothesis of oxygen storage. 

 It should be added that no mechanism is known in any animal by 

 which it is possible to store oxygen, beyond the quantity taken up 

 by the respiratory pigments. 



Dubois [1896], Pembrey and Weinland and Riehl [1907], believe 

 that during the hibernation a conversion of fat into glycogen takes 

 place and that the glycogen is used up as combustion material during 

 the process of awakening. Weinland and Riehl have supported this 

 hypothesis by finding during the process of awakening a high respira- 

 tory exchange with a quotient of about I *o indicating, in their opinion, 

 an exclusive combustion of carbohydrate, and they have determined 

 further [1908] the total amount of glycogen present in marmots 

 during sleep and just after awakening. They found from 3 to 4 gr. per 

 kg. in three sleeping animals and 1*9 in a fourth just after awakening. 

 The glycogen determinations of Weinland and Riehl are too few in 

 number to inspire confidence. Similar determinations have been made 

 by Hdri on bats, but the rather discordant results do not show any 

 increase in glycogen during the hibernation. There is, therefore, no 

 satisfactory evidence to demonstrate any formation of glycogen during 

 the hibernation, but on the other hand the possibility that such a for- 

 mation takes place cannot be denied. 



Nagai points out that the amount of glycogen which must be 

 stored in order to explain such low quotients as found by Pembrey or 

 even by Regnault and Reiset would be far in excess of the quantities 

 which can be found in the animal body, but as these quotients are 

 untrustworthy the demonstration is superfluous. The respiratory 



