Intelligence mid Miscellaneous Articles, 563 



whole of the absorbed gas; but the more frequently fresh carb<»iic 

 acid is added to the blood, the greater must be the quantity of gas. 

 This is also true in practice; but alter renewing the carbonic acid 

 3 or 4 times, the increase in the quantity of gas was found to be so 

 small, that it fell within the limits of error of observation. More- 

 over, all the experinients were carried out under the same conditions. 

 About 400 cubic centimetres of blood were usually employed; a 

 smaller quantity was only used for some experiments. Too small a 

 quantity could not be applied, as the amount of gas obtained is very 

 small. The volume of carbonic acid, which was each time shaken 

 with the blood, was never less than that of the blood itself; nor could 

 much larger quantities be taken, because the vessels when com- 

 pletely filled with mercury would be managed with too much diffi- 

 culty, and would be readily broken. Even in their present size con- 

 taining about 700 cubic centimetres, they must be made of exceed* 

 ingly strong glass. They are tall and cylindrical, 'with a narrow 

 neck, and are graduated in cubic centimetres. 

 .! The quantity of oxygen which, as shown by these experiments, 

 the blood was capable of absorbing, is, as the author has proved, suf- 

 ficient to allow of the supposition that the whole quantity of air in- 

 spired is absorbed by the blood ; but it is doubtful whether the arte- 

 rial blood contains as much oxygen as that repeatedly shaken with 

 atmospheric air, and whether the quantities obtained were but a 

 small portion of the oxygen really absorbed. 



To decide this, the experiments were varied, so that the blood 

 was first agitated with constantly renewed quantities of carbonic 

 acid, to remove the whole of the oxygen and nitrogen absorbed. 

 The blood was then repeatedly shaken with measured quantities of 

 atmospheric air, and the remaining air was again measured, and the 

 quantity of carbonic acid, oxygen and nitrogen ascertained by the 

 method previously described, when the quantity of oxygen and 

 nitrogen absorbed was found. From numerous experiments con- 

 ducted in this manner, the minimum amount of oxygen absorbed 

 amounted to 10 per cent, and the maximum to 16 per cent, of the 

 volume of the blood. In several experiments as much as 6*5 per 

 cent, of nitrogen was absorbed. , 



In one of these experiments calves' blood wafi uninterruptedly 

 shaken with atniospheric air ; it was then repeatedly agitated with 

 carbonic acid. By this treatment it yielded 11 "6 percent, of its 

 volume of oxygen, but absorbed 154*9 per cent, of carbonic acid. 

 This blood was then shaken with separate portions of a measured 

 quantity of atmospheric air ; it thus absorbed 15*8 per cent, of oxy- 

 gen, yielding at the same time 138'4 per cent, of carbonic acid. 

 Finally, it was again sliaken with carbonic acid, and again yielded 

 9*9 per cent, of oxygen, whilst it absorbed 92*1 per cent, of carbonic 

 acid. jiiii'KUB i !'jT>y/ii i-^' 'M'V 



It is thus evident that by agitation with. !oarbonic acid Ave cap 

 separate almost the whole of the oxygen absorbed by the blood, 

 which would be the most striking proof that the oxygen is not che- 

 mically combined with the blood, but exists in it merely as absorbed. 



