454 An Account oj some Experiments on Animal Heat, 



thermometer in less than a quarter of a minute. The mixture 

 now was instantly made, and by the same thennonieter the 

 highest temperature after mixture was discovered. ' 



The four followine; trials were made on tl^.c blood of two lambs, 

 both about five moutlis old. The temperature of the air wa^ 60. 



Cold water o7'5. Venous blood 100. Mixture 80 ; after 

 one minute 78 5. 



\A"ater 58. Arterial blood 103. Mixture 80 ; after one mi- 

 nute 79. 



Water .58. Venous blood !01*5. Mixture 79 5 after one 

 minute 78' 25. 



Water 58. Arterial blood lOG-5. Mixture 81; after one 

 minute 80. 



The rate of coolinc; was not noticed after the first minute had 

 elapsed, as the blood then generally began to coegulatc. The 

 specific gravity was only ascertained in the two last trials ; that 

 of the venous Idood was found to be 1050, and that of tlie arterial 

 1049; and hence allowing, as before, one degree of the cooling 

 effect to be jjroduced bv the receiver, the capacity of venous 

 blood for heat appears to be •852, and that of arterial blood 

 •839. 



It is evident that these trials admit of less accuracy than the 

 preceding ; and much more corifidence, it appears to me, is due 

 to the third series of experiments ; so that, if required, I should 

 be inclined to give the riumbers thence deduced, as the greatest 

 approximation to the truth. 



2. On the comparative Tempnalvrps of venous and a7;terial 

 Elood, and of different Paris oJ the animal Body. 



To endeavour to ascertain the comparative temperature of 

 venous and arterial blood, I have made a considerable number 

 of experiments ; some of- which on lambs, sheep, and oxen, it 

 will be sufficient for me in this place to describe. In each in- 

 stance, a long incision was made through the integuments ; the 

 jugular vein was laid bare, and the exact seat of the carotid 

 artery found. The vein was then opened, and a small delicate 

 thermometer introduced, and thrust about an inch up the vessel 

 beyond the wounded part ; and as the bulb of the instrument 

 was small, the flow of blood was not stop])ed. When the mer- 

 cury was stationary, its height was marked. The carotid artery 

 next was divided, aiid the thermometer was immersed in the 

 current of blood, and left there till it ceased to rise. 



The following are the results of five experiments made on 

 lambs, all of which were about three months old. The thermo- 

 meter in the shade stood at 65. 



1. 'Venous 



