?76 A^otices respecling New Books. 



In all aniina's carbon is a necessary constituent substance^ 

 and the means (if acquiring it nuist be as constant as its ex- 

 pulsion (luring living action has been shown to be; and from 

 no other source than through the organs of digestion and 

 secretion can il be conceived to be deriveiJ. To these or- 

 gans of digestion, assimilation, and secxetion alone, are we 

 enabled to trace it ; but our knowledge of the theory of these 

 functions in aniiDils as in vco-ctables is extrenielv limited 

 and i IT) perfect. We have, indeed, of late succeeded in get- 

 ting rid of iTiiich error and absurdity, but have not, in any 

 instance, attained to complete kiioivledge." 



The la3t chapter of this excellent and logical inquiry in- 

 vestigates '•' the Phasnomena whieli arise IVom the Changes 

 induced on the Air by the living Functions of Vegetables 

 and Animals." The general inconsistency and irreconcilca- 

 bleness of the various opinions'and experiments on this sub- 

 ject have not deterred Mr. Ellis from selecting the principal 

 facts which lend to explain the phecnomena of respiration 

 and animal heat. 



" Animal heat," says the author, «' in all the amphibia 

 mentioned, whether they Inhabit the air or the water, seems 

 to follow nearly that of the medium in which they are 

 placed; and their standard temperature cannot, inconse- 

 quence, be restricted to any fixed point, but must be con- 

 sidered always in relation to that of their surrounding me- 

 duuTi. Nevertheless, the low degree of heat which these 

 animals possess,- is a proof that they have within themselves 

 a power of producing heat. The loss of heat which insects 

 sufler under cold, the fall of temperature in worms under 

 melting snow, demonstrate that the surrounding medium,, 

 wliether it be air or water, is constantly di iwing off their 

 beat -, v.'hich renders necessary as constrni a reproduction of 

 it. it is also evident, from the exjieriments detailed, that 

 during a «tate of torpor the temperatr.rc even of the wann- 

 blooded animals exceeds only in a small degree that of the 

 atmosphere by which their torpor is induced. But on pass- 

 ing into this torpid state, under which the temperature so 

 greatly falls, the motion of the blood in animals gradually 

 dtclinesy and at length, in some cases, wholly ceases'. All 



the 



