294 



DR. DAVY'S ACCOUNT OF SOME EXPERIMENTS ON THE BLOOD. 



fully deprived of air by the air-pump. Observing the same precautions as before, a 

 portion of venous blood from a Sheep was received into each of them. When less 

 than half of the water and of the solution, as well as could be guessed, was expelled, 

 the vials were closed with the glass stoppers belonging to them, and instantly im- 

 mersed in water, and as soon as possible subjected to the air-pump. The results of 

 exhaustion in the two instances was perfectly distinct. From the blood mixed with 

 water gas was disengaged ; there was a continued ascension of bubbles. From the 

 blood mixed with the alkaline solution no gas was liberated, excepting a bubble or 

 two, which might fairly be considered as entangled air derived from contact of the 

 blood with the stopper. 



A similar comparative trial was instituted with arterial blood of the Sheep, and the 

 results also were similar and equally well marked. 



Considered as test experiments, the first inference from these results is, that car- 

 bonic acid gas, or an air absorbable by a solution of potash, is disengaged both by 

 venous and arterial blood in vacuo ; and next, that no other gas is disengaged from 

 either of them, neither oxygen nor azote, each of which is unabsorbable by the solu- 

 tion in question. I have repeated the experiment twice on the venous blood of Man, 

 and twice on the venous blood of the Sheep, and twice on the arterial blood of the 

 latter, without variation of results ; and they are more to be depended on, as the al- 

 kali has the effect of preserving the blood liquid. 



I may mention another method which I have employed as a test experiment ; and 

 first in relation to carbonic acid. If the blood contain a notable portion of this gas 

 capable of being extricated by the air-pump, it necessarily follows, that when subjected 

 to the action of the air-pump, and deprived as far as possible of its fixed air by this 

 means, it will be capable of absorbing a larger quantity of carbonic acid than pre- 

 vious to the exhaustion. The following Table contains the results of three compara- 

 tive trials on the venous blood of the Sheep, its fibrin separated or detached in the 

 usual manner. 



Table showing the absorption of carbonic acid gas by 



Although I have thought it right to notice these results, and although they are in ac- 

 cordance with the preceding, I do not attach value to them, excepting as tending to 

 show that the quantity of carbonic acid gas extracted by the air-pump, when the 

 blood affords it in vacuo, is small. 



The same mode of reasoning suggested comparative trials of the absorbent power 



