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



1st. On Arterial Blood. 



1. Fifty-three measures of this blood were agitated over mercury with forty-six 

 measures of nitrous gas ; there was a diminution of volume of seventeen measures. 



2. Fifty-three measures of the same blood (another portion) were agitated with 

 nine of oxygen ; two measures were absorbed. 



3. Fifty measures of this blood, so treated with oxygen, were agitated with forty- 

 seven of nitrous gas ; there was a diminution of twenty-two measures. 



2nd. On Venous Blood. 



1. Fifty-three measures of this blood were agitated with fifty of nitrous gas ; ther^ 

 was a diminution often measures. 



2. Fifty-three measures (another portion) were agitated with ten of oxygen ; five 

 measures were absorbed. 



3. Fifty-one measures of blood so treated were agitated with forty-nine of nitrous 

 gas ; there was a diminution of seventeen measures. 



The residual air in each instance was examined and was found to be a mixture of 

 nitrous gas and azote without carbonic acid gas. The azote, it may be presumed, 

 was introduced with the nitrous gas ; it was in the same proportion as that which 

 adulterated it, viz. about four per cent. That the residual air was free from carbonic 

 acid was inferred from the circumstance, that in comparative experiments with and 

 without addition of a portion of solution of caustic alkali, there was no difference in 

 the proportion of nitrous gas absorbed : and it was corroborated by another circum- 

 stance, viz. that after the absorption of the nitrous gas, the blood was capable of ab- 

 sorbing seventy-five per cent of carbonic acid gas*; and further by the result that 

 when nitrous gas is added not to saturation, the whole of it is absorbed -f-. 



As regards the blood itself, the colour of both venous and arterial was altered; both 

 were rendered darker and browner, as if a minute quantity of nitric acid had been 

 added to them, a change long known to be occasioned by nitrous gas. In the de- 

 gree of change there was however a difference; in the instance of arterial and of oxy- 

 genated arterial blood, it was more strongly marked than in that of the venous. 



In conjunction with the unsuccessful attempts with the other gases already men- 

 tioned, do not the results just described indicate that a portion of oxygen exists in 



* To some venous blood of a Sheep which absorbed 182 per cent, of carbonic acid gas, so much of a solution 

 of pure hydrate of potash was added, that it absorbed 218 per cent, of the acid gas ; seventeen measures of this 

 blood with excess of alkali, agitated with fifty-one of nitrous gas, absorbed 5*5 measures ; sixteen of the blood 

 without the excess of alkali absorbed five measures : thirty-four measures of carbonic acid gas were added to 

 the latter, the excess of nitrous gas being left in the tube ; on agitation twelve measures of the carbonic acid 

 were absorbed. 



\ In one experiment eighty-four measures of the venous blood of the Sheep were agitated with ten of ni- 

 trous gas over mercury ; the whole of the gas was absorbed : twelve of oxygen were added ; on agitation again 

 there was no further absorption. 



