214 THE INDUCTIONS OP BIOLOGY. 



from prolonged abstinence. Even fish, though much more 

 active than most other aquatic creatures, appear to undergo 

 hut little loss of substance when kept unfed during consider- 

 able periods. Reptiles, too, maintaining no great tempera- 

 ture, and passing their lives mostly in a state of torpor, suffer 

 but little diminution of mass by waste. When, however, we 

 turn to those higher orders of animals which are active and 

 hot-blooded, we see that waste is rapid: producing, when 

 unchecked, a notable decrease in bulk and weight, ending 

 very shortly in death. Besides finding that waste is 



inconsiderable in creatures which produce but little insensible 

 and sensible motion, and that it becomes conspicuous in 

 creatures which produce much insensible and sensible motion ; 

 we find that in the same creatures there is most waste when 

 most motion is generated. This is clearly proved by hyber- 

 nating animals. " Valentin found that the waking marmot 

 excreted in the average 75 times more carbonic acid, and 

 inhaled 41 times more oxygen than the same animal in the 

 most complete state of hybernation. The stages between 

 waking and most profound hybernation yielded intermediate 

 figures. A waking hedgehog yielded about 20.5 times more 

 carbonic acid, and consumed 18.4 times more oxygen than 

 one in the state of hybernation." * If we take these quanti- 

 ties of absorbed oxygen and excreted carbonic acid, as in- 

 dicating something like the relative amounts of consumed 

 organic substance, we see that there is a striking contrast 

 between the waste accompanying the ordinary state of 

 activity, and the waste accompanying complete quiescence 

 and reduced temperature. This difference is still more defi- 

 nitely shown by the fact, that the mean daily loss from 

 starvation in rabbits and guinea-pigs, bears to that from 



* In connexion with this matter I add here a statement made by Prof. 

 Foster which it is difficult to understand: "Indeed it has been observed 

 that a dormouse actually gained in weight during a hybernating period ; it 

 discharged during this period neither urine nor faeces, and the gain in 

 weight was the excess of oxygen taken in over the carbonic acid given out." 

 (Text-book of Phytiology, 6th ed., Part II, page 869.) 



