1SI4.J during (he CoaguIalio?i of the Blood. 141 



" In tlii? experiment, therefore, the extrication of caloric during 

 the copulation of the blood was rendered sensible by the thermo- 

 meter for 20 minutes after the process had commenced ; and was at 

 one period so great as to raise the thermometer, in this coo! apart- 

 ment, 3-1° of the centigrade scale, which is equal to 6'3° Fah'r. 



" That a similar extrication of heat was not apparent in Mr. 

 Hunter's experiment on the blood of the turtle, may have been 

 owing to his not having placed the bulb of the thermometer alter- 

 nately in the coagulating and yet uncoagulated part ; and partly, 

 perhaps, to the slowness with which he informs us the process 

 went on. 



" We may regard it, therefore, as established, that when part of 

 the blood thus spontaneously passes from a fluid to a solid state, 

 caloric is extricated, in the same manner as when other fluids 

 undergo a similar change." 



Farther than this, my notes did not then extend. 



But during last winter I had an opportunity of trying this expe- 

 riment several times, on venous blood drawn from persons labouring 

 under inflammatory complaints, and the result was always precisely 

 similar. The following is a note of one of these experiments : — 



Jan. 22, IS 14. I received three ounces of blood from the me- 

 dian vein of a man, aged 40, labouring under pneumonia, into a 

 tall glass vessel, and immediately introduced into it a delicate Fah- 

 renheit thermometer, the bulb touching the bottom. The tempe- 

 rature of the blood in this situation was 76°. In two minutes fluid 

 collected at top ; and in two more a very thin film appeared on 

 the surface of this size, and the thermometer was then exactly 74°. 

 In four minutes more, that is, eight minutes after the blood had 

 been drawn, a soft coagulum was formed to the depth of an inch 

 from the top, and the thermometer (the bulb being still at the 

 bottom) was 7-i°- I now raised the bulb smartly into the middle of 

 this coagulum, and instantly the mercury rose to 85° (that is, 12°); 

 and when I depressed it again to the bottom, where the blood was 

 still fluid, the mercury immediately sunk to 7-3°. I repeated this 

 several limes with similar success. The temperature of the apart- 

 ment during the experiment was 55°. 



I have tried this experiment again, within these few days, on 

 blood drawn from the arm of a middle aged man, labouring under 

 an affection of the heart, and the result was similar. 



On carefully reviewing all these experiments, 1 cannot discover 

 any source of fallacy connected with them, which should lead me 

 !<> hesitate in deducing from them ' i conclusion as formerly, 



viz. that calorie is extricated during the coagulation of blood, and 

 therefore that the blood is m ion to the general law applicable 



to all other fluids in this P p< '. 



That my friend Dr. Daw has been led to adopt an opposite 

 opinion in consequence of hi experiments on lamb's blood, has 

 obviously arisen from his not i been aware of tbe importance 

 Oi moving the thermometers in his experiments; — a circumstance 



