364 RESPIRATION. 



fact first observed by Sacc, that the weight of the body is generally, 

 although not constantly, increased during the hybernation of 

 marmots. 



These inquirers arrived at similar results in reference to the 

 influence of hybernation, or the sleep induced by exposure to 

 cold, in their experiments on lizards. 



It may readily be seen, from the ratio of the oxygen contained 

 in the expired carbonic acid to the inspired oxygen, that only a 

 very small quantity of fat can undergo oxidation in the body of 

 the hybernating marmot (while the nitrogenous substances are still 

 less implicated in the process), for the substance consumed must 

 be far richer in hydrogen ; the carbon being to the hydrogen as 

 21*26 : 5'41, or, according to the atomic weights, very nearly as 

 2 : 3. (This substance would therefore exhibit a composition not 

 very often met with in organic chemistry, namely, C 6 H 9 + x H O.) 

 If, with this abundance of hydrogen, ammonia or any ammoniacal 

 alkaloid should be formed, we need scarcely wonder at the great 

 absorption of nitrogen which Reiset and Regnault observed. At 

 the same time we must beware of drawing too wide a conclusion ; 

 for besides the hypothesis already advanced, it would be con- 

 ceivable, and perhaps more probable, that the oxygen absorbed by 

 these animals during their hybernation combines with only the 

 one part of the hydrogen in one constituent of the body, and thus 

 generates relatively even more water than carbonic acid ; thus the 

 atomic aggregate C 2 H 3 would be abstracted from such a substance 

 by the inspired oxygen, and the substance itself would not there- 

 fore be perfectly oxidised. 



Regnault and Reiset found that marmots, when they awake 

 from their hybernation, exhale an extremely large quantity of 

 carbonic acid, and consume more oxygen than at a subsequent 

 period of their waking state an observation which corresponds 

 with the fact noticed both by Prout and Vierordt in their experi- 

 ments on man, that the act of waking was followed by a very 

 abundant excretion of carbonic acid, which again diminishes in 

 half-an-hour or an hour. 



Bodily exercise increases the exhalation of carbonic acid in 

 the same manner as we have shown that a state of rest diminishes 

 it a fact which might have been inferred from the above relations 

 of the respiratory movements, but which is also proved by direct 

 observation. Seguin,* one of our earliest observers, found that he 



* Op. cit., p. 357. 



