Gases of the Blood 943 



CO, per 100 cc. of blood (beef blood at 16°), the largest part (96.4 

 cc.) of this acid is dissolved in the blood, since it follows Dalton's 

 Law in its relation to the barometric pressure, and since the rest 

 (59.7 cc.) is combined in the form of bicarbonate or phosphocar- 

 bonate, because it escapes this law. 



Now our analyses have shown us that in arterial blood only 

 very rarely are there 50 volumes of C0 2 . We may say then that 

 regularly the arterial blood contains only C0 2 in combination, both 

 weak and strong. On the contrary, in the blood of the right heart 

 we have found, on the average, higher proportions of C0 2 ; this 

 blood then seems to contain in addition C0 2 simply dissolved. 



This leads us then to think that respiration, so far as carbonic 

 acid is concerned, consists chiefly and perhaps exclusively of an 

 exhalation of the excess of carbonic acid simply dissolved, the part 

 combined in the state of bicarbonate or phosphocarbonate being 

 only slightly or not at all modified. In perfect respiration, at its 

 regular rhythm, no dissolved acid should remain in the arterial 

 blood. 



With the purpose of gaining light upon this point, which is im- 

 portant for the general theory of respiration, I began experiments 

 with the following method. I draw from an animal arterial blood, 

 the carbonic acid tension of which I determine immediately by 

 means of a vacuum and heat. Then for two hours, by means of the 

 water motor (See Fig. 42), I agitate another sample of the same 

 blood in a flask full of pure carbonic acid: a rubber bladder, also 

 full of C0 2 and communicating with the flask, prevents absorption 

 from lessening the gaseous tension. After this time, another an- 

 alysis. I then subtract from the number found the quantity of CO, 

 which the blood would be capable of dissolving at the actual tem- 

 perature (the observations of M. Fernet permitted me to use Bun- 

 sen's tables for the coefficients of solubility), and the remainder 

 should show whether there is still dissolved C0 2 in the arterial 

 blood. For greater clarity, let us take an example: let us suppose 

 that the arterial blood has given 40 volumes of C0 2 , and that after 

 agitation at 16° it contains 138; the coefficient of solubility being 

 96.4, we see that the salts of the blood required for saturation 

 138 — 96.4 = 41.6; therefore, in the blood they were not at the maxi- 

 mum of carbonization, because for that they lacked 1.6 volumes 

 of C0 2 . 



Here are some experiments made by this simple method. The 

 first two include in addition the analysis of the gas of the blood 

 of the right heart: 



