942 Experiments 



that under the influence of decreased pressure, the blood first ioses, 

 proportionately, its oxygen more quickly than its carbonic acid; 

 then equilibrium is established; then the carbonic acid escapes in 

 larger proportion; and finally, the pump brings only carbonic acid. 



The same thing is true even when it is a question of blood in 

 which the proportion of carbonic acid is much higher than the 

 average. The experiments on carbonic acid poisoning give us 

 numerous examples. 



In Experiment DCXIV, in Blood C which contained C0 2 103.6 



co 2 



and O., 18.2, the ratio being 5.7, the first strokes of the pump 



o 2 



co 2 



brought a gas in which the ratio was 5.2, whereas the last 



strokes gave the ratio 6.0. Similarly, in Experiment DCXV, for 



CO, 

 Blood E (CO, 97.5; 0„ 13.7), the ratio being 5.2, we had for 



o 2 



the first tubeful of gas the ratio 4.7, and for the second, the ratio 9. 

 The vacuum of the gas pump, used as I specified, combined with 

 the temperature of boiling water, removes almost all the carbonic 

 acid contained in the blood. The later addition of a strong acid 

 sets free only minimal quantities, sometimes none at all: the ex- 

 periment which I have just reported gives a satisfactory example of 

 that. 



We know how much the opinions of physiologists and chemists 

 have varied in regard to the carbonic acid which can be extracted 

 by the pump (acid which is "free", "dissolved", "ausgepumpen" of 

 the Germans) and that which resists a vacuum aided by heat (acid 

 which is "combined", "bound", "gebunden"). Earlier authors 

 thought the latter very abundant (Lothar Meyer estimated it at 

 28.58 as against 6.17 of the free acid) ; but the analyses of Schoffer, 

 Setschenow, Pfliiger, etc., have successively reduced the proportion 

 to what we have observed ourselves. 



In blood artificially saturated with carbonic acid, this gas is in 

 three forms: simply dissolved, weakly combined (bicarbonates and 

 phosphocarbonates) , or strongly combined (carbonates). But in 

 what form does it exist in normal blood, both arterial and venous? 



In these natural conditions is there simply dissolved carbonic 

 acid? M. Fernet (loc. cit., page 209), had concluded from his ex- 

 periments that in saturated liquid, that is, containing 156.1 cc. of 



