1894.] Oxygen upon the Coagulability of the Blood in Vivo. 283 



Eesults of Experiments in which Oxygen was withdrawn ly the Sub- 

 stitution of Hydrogen for Atmospheric Air. 



I have employed this method in 29 experiments. In 15 of these 

 experiments a diminution of coagulability was observed to result 

 from the inhalation of hydrogen. In 14 other experiments an in- 

 crease of coagulability was noted. With respect to the latter 



esults, the following points are to be noted : (a) The increase of 



jagulability was invariably confined within very moderate limits ;* 

 (6) in 2f out of the 14 experiments expiration was found to have 



een obstructed by an accidental compression of the tracheal tube. 

 The results of these experiments are patently ambiguous. On the 

 >ne hand we have a bare majority of experiments or (if we subtract 

 the experiments in which expiration was accidentally obstructed) a 



xajority of only 15 to 12 experiments in favour of the result that 

 the inspiration of hydrogen conditions a diminution, and not an 

 increase, of blood coagulability. On the other hand, it is evident that 



lere is nothing in these experiments when taken by themselves to 

 justify a conclusion as to whether it is the decrease or the increase of 

 coagulability which is to be regarded as the effect of the withdrawal 

 jf the oxygen. In such a case the only available method of interpre- 

 tation consists in subducting from the aggregate of the observed 

 Dhenomena such phenomena as we know by previous inductions to 

 be the result of disturbing factors which cannot be eliminated from 

 the experiments. The accumulation of carbonic acid in the blood, 

 which occurs when the inevitable dyspnoeic standstill of respiration 

 takes place, or when (as in rabbit 176 and dog 4) expiration is acci- 

 dentally obstructed, is just such a. disturbing factor, and the effects of 

 this disturbing factor must, in accordance with our previous induc- 

 tions, manifest themselves in an increased blood coagulability. We 



lay, therefore, legitimately assign to this cause all the phenomena of 

 increased blood coagulability which came under observation in the 

 hydrogen experiments. The residue of the observed phenomena, in 

 other words the diminution of blond coagulability, then emerges as 

 the effect of the absence of oxygen from the inspired air. 



If the above train of argument is valid, we must conclude that the 

 diminution of the oxygen of the blood conditions a diminution of 

 coagulability. 



* Coagulation-time was never found reduced below 1 minute 30 seconds (vide 

 protocol rabbit 176). Coagulation-times of less than 1 minute are frequent (vide 

 protocols passim) during inspiration of carboi'io acid and oxygen. 



t Vide protocols of rabbit 176 and of dog 4. 



