Gases of the Blood 643 



sions from the analyses of M. Fernet on the other, a contradiction 

 which could be only apparent, and which demanded explanation. 



But in the first place, M. Fernet could change the pressure only 

 in very narrow limits; for whole blood, the pressures had varied 

 from 741 to 580 millimeters. I should inquire what would happen 

 in experiments in which the pressure was diminished to the neigh- 

 borhood of a vacuum on the one hand, and increased several 

 atmospheres on the other. 



The problem was infinitely easier to solve than in the time of 

 M. Fernet; in fact, I had at my disposal means of extracting all the 

 gases of the blood, which the physicist had not been able to obtain, 

 in spite of all his efforts. He therefore had had to use direct meas- 

 urement of the gases absorbed, that is, measuring the decrease in 

 volume of gases agitated with blood which had previously been 

 deprived of those which it contained at first; a series of very deli- 

 cate operations, which required a very complicated set of tools, and 

 the use of glass apparatus which would not permit high pressures. 

 On the contrary, thanks to the mercury pump, after agitating the 

 blood in a large quantity of air, under determined pressures, I 

 could extract the dissolved gases easily and completely. I could 

 thus make a large number of analyses, which, without claiming the 

 exactness of second decimals, are quite accurate enough to reach 

 the goal I had set for myself. 



I shall report some of them; but I must first thank M. Grehan'c, 

 who was then taking my place on the Faculte des Sciences of Paris, 

 and who, at my request, consented to carry out a great number of 

 them. 



1. Pressures Lower Than One Atmosphere. 



My first experiments were simply made by placing in a flask 

 with a wide mouth (Fig. 41) a certain quantity of defibrinated 

 blood which I then agitated vigorously, without completely closing 

 the flask. When the blood was thus saturated with oxygen, I fast- 

 ened the flask to the end of a long cord and whirled it like a sling, 

 which procedure brought out very rapidly the air bubbles which 

 had remained suspended in the viscous liquid. I then took with a 

 graduated syringe a certain quantity of blood, from which I ex- 

 tracted the gases by the mercury pump. 



The mouth of the flask was then carefully closed by a rubber 

 stopper through which passed a thermometer and two glass elbow 

 tubes. One of these tubes dipped into the blood, so that one could 

 obtain samples of the blood through it by means of cock R. Cock R' 



