126 RESPIRATORY EXCHANGE OF ANIMALS AND MAN 



TABLE XXXIII. 



During the sleep the respiratory quotient is low and probably 

 even generally below that corresponding to a complete catabolism of 

 fat (071). Some experimenters (Pembrey, Valentin, Voit [1878], 

 Regnault and Reiset [1849]) have observed extremely low respiratory 

 quotients even down to OT (Valentin) or 0*26 (Pembrey), but according 

 to Nagai, to whose criticism the writer can on the whole subscribe, the 

 very low values are unreliable, and the average quotient during 

 hibernation is probably about O'6 or a little over. Hari [1909, 2], like 

 Nagai, found fairly high respiratory quotients (about 0*68) in hibernat- 

 ing bats. In one animal, however, the quotient was during the whole 

 period of observation from February 9 to March 7 considerably lower 

 on an average O'$$. 



It should be borne in mind that respiratory quotients representing 

 faithfully the catabolic processes going on in the body can be obtained 

 only when the store of carbon dioxide either remains unaltered or can 

 be considered as insignificant compared with the quantities exhaled 

 during the determination. Changes in body temperature will almost 

 certainly affect the carbon dioxide absorbed in the tissues, and even 

 slight changes in the pulmonary ventilation, which are apt to occur 

 when the sleeping animal is disturbed by the manipulations involved in 

 the experiment, will do the same, and may therefore have a disastrous 

 effect upon the determination in experiments of short duration. 



Various hypotheses have been put forward to explain the low 

 quotients observed during hibernation. Regnault and Reiset, who 

 first observed the low quotient in a sleeping marmot, were of opinion 

 that oxygen might in some form be stored within the organism for 

 later use especially during the process of awakening. This hypothesis 

 has been supported by the observation made repeatedly that the body 

 weight of a hibernating animal may increase, and further by the fact 

 that these animals during their sleep will endure oxygen want for a 

 considerable period (up to 4 hours, Spallanzani). Valentin, Voit, and 



