£00 ANIMAL HEAT. 



scription, and the circulation of the blood is afterwards main- 

 tained by means of artificial respiration, the generation of heat 

 is found to be as completely destroyed, as if the head had been 

 actually removed, 

 until the brain Under these circumstances, if the artificial respiration is 

 recovers. ^ e ^ t U p unt jj t j ie e ff ects f t j ie p j son ce ase, as the animal 



recovers his sensibility, so does be also recover the power of 

 generating heat ; but it is not till the nervous energy is com- 

 pletely restored, that heat is produced in sufficient quantity to 

 counteract the cold of the surrounding atmosphere*. 

 In such cir- In the experiments formerly detailed, as well as in those 



ctimstances the j ns t mentioned, I observed that the blood underwent the usual 

 chemical ,./-,., ,. .,1 , 



changes from alteration of colour in the two systems of capillary vessels, 



artificial respi- while carbonic acid was evolved from the lungs at each expira- 

 nsual. tion j and hence I was lead to believe, that the respiratory 



function was performed nearly as under ordinary circum- 

 stances, and that the usual chemical changes were produced 

 on the blood. It appeared, however, desirable to obtain some 

 more accurate knowledge on this point, and I have, therefore, 

 instituted a series of experiments, for the purpose of ascertain- 

 ing the relative quantities of air consumed in breathing, by 

 animals in a natural state, and by animals in which the brain 

 has ceased to perform its office, and I now have the honour of 

 communicating an account of these experiments to this society. 

 It has been shewn, by Messrs. Allen and Pepys, first,f that 

 every cubic inch of carbonic acid requires exactly a cubic inch 

 of oxygen gas for its formation ; secondly, j that when respi- 

 ration is performed by a warm-blooded animal in atmospheric 

 air, the azote remains unaltered, and the carbonic acid exactly 

 equals, volume for volume, the oxygen gas, which disappears. 

 The watery There is, therefore, reason to believe, that the watery vapour 



vapour which wn j c j, ebca p es V vith the air In expiration, is not formed from 

 escapes m res- * r 



piration, is not the union of hydrogen with oxygen in the lungs, but that it is 

 formed during 



the process, * The poison employed in this experiment should be the essential oil 



of almonds, or some other, the effects of which speedily suhside. If 

 the wooiara is employed, so long a time elapses before the poison 

 ceases to exert its influence, that it becomes necessary that the experi- 

 ment should be made in a high temperature, otherwise the great loss of 

 heat which takes place, i-> sufncient to prevent iccoveiy. 

 t Phil. Trans. 1807, Pari II. 

 tPhil. Trans, mca, Part II. Ibiil. 1809, Part IJ. 



exhaled 



