748 Experiments 



bonates, if the organism did not unceasingly furnish the venous 

 blood with a constant source of this gas. We shall return to these 

 data in another chapter, but it would be interesting to see, by a 

 simple experiment, in which the same blood would be forced by a 

 pump to pass constantly through the lungs, in which artificial res- 

 piration would be maintained, how much carbonic acid this blood 

 could lose. 



Before leaving this subject, let us say that the carbonic acid re- 

 appears but slowly in normal proportion in the arterial blood, when 

 the superoxygenated animal recovers and lives. In Experiment 

 CCLXXXIX, at the end of 1 hour and 15 minutes the proportion of 

 carbonic acid was only 19.0; in Experiment CCXCIII, after 2 hours 

 and 40 minutes, it had risen only to 26.5; but in Experiment 

 CCLXXXI, at the end of 67 minutes it had returned to its original 

 figure, 31.5. Let us note that this tendency to return to the normal 

 proportion does not always indicate that the animal will survive, 

 as Experiment CCLXXX shows. 



Excretion of Urea. I now come to the urea. The experiments 

 were conducted like those in the case of diminished pressure. The 

 animal, subjected to a fixed diet for several days, was kept for 

 several hours in compressed air, with a suitable current of air. The 

 urine voided spontaneously or collected with a catheter in the pre- 

 ceding 24 hours was compared with that given in the 24 hours in 

 which the compression took place. The account of the experiments 

 will give the necessary details. 



Experiment CCCVII. Dog weighing 12 kilos, eats every day at 7 

 o'clock in the morning a soup composed of 250 gm. of bread, 250 gm. 

 of meat, and 500 gm. of water. 



July 25, at 8 o'clock in the morning, catheterized the animal, 

 which was then placed in a cage where the urine can be collected; 

 he does not urinate, and July 26, at 8 o'clock, another catheterization 

 gives 280 cc. of urine. This urine, analyzed by the Yvon process, 

 gives 4500 cc. of nitrogen, that is, 12.1 gm. of urea. 



July 26, from 9 o'clock to 3 o'clock, is subjected to a pressure of 

 8 atmospheres, under a current of air. Decompressed from 3 o'clock 

 to 5 o'clock, is taken out in good condition. His rectal temperature 

 is 35.5°. 



July 27, at 8 o'clock in the morning (rectal temperature 35.7°) 

 he is catheterized and the urine thus obtained is added to what he 

 voided spontaneously. The total is 350 cc. of urine, which gives only 

 1398 cc. of nitrogen corresponding to 3.7 gm. of urea. I must add that 

 the animal would eat only half his meal. 



July 28, at 8 o'clock in the morning, catheterized again; there are 

 520 cc. of urine giving 3838 cc. of nitrogen, that is, 10.3 gm. of urea. 

 During this day, the animal had absolutely refused to eat. 



