Compressed Air; Low Pressures 765 



Experiment CCCXXVI. February 9. Dog weighing 10.8 kilos, kept 

 on a diet and used to staying in cages and in the compressed air 

 apparatus in Figure 33. 



February 12 at 6 o'clock in the evening, catheterized. 



February 13. Remained at normal pressure; catheterized at 6 

 o'clock in the evening; in 24 hours gave 650 cc. of urine .... A 



February 14. From 9 o'clock in the morning to 5:45, kept under 

 current of air at the total pressure of three atmospheres. Catheterized 

 at 6 o'clock; gave in all 610 cc. of urine B 



February 15. Same pressure; urine of 24 hours, 1080 cc C 



February 16. Normal pressure; urine of 24 hours, 1350 cc D 



February 17. Normal pressure; urine of 24 hours, 1370 cc E 



Analysis of urine by the Yvon method. 



A (normal pressure) contained 7.9 gm. of urea. 



B (3 atmospheres) contained 10.4 gm. of urea. 



C (3 atmospheres) contained 9.0 gm. of urea. 



D (normal pressure) contained 9.1 gm. of urea. 



E (normal pressure) contained 8.4 gm. of urea. 



It is quite evident that since the catheterization was made im- 

 mediately after the decompression, urine D contained a part of the 

 products of katabolism formed during the stay in compressed air; 

 it ought therefore to be included in the urine of the compression. 

 Taking this into consideration, we see that the urea increased as a 

 result of the daily stay of 9 hours in air at 3 atmospheres; indeed, 

 it rose then on the average to 9.5 gm., while at normal pressure it 

 was on the average only 8.1 gm. 



C. Chemical Phenomena of Respiration. 



I made a certain number of attempts to estimate the quantity of 

 carbonic acid formed by an animal placed sometimes at normal 

 pressure, sometimes at increased pressure without exceeding 5 

 atmospheres. But I encountered experimental difficulties which 

 prevented me from reaching a conclusion. 



To obviate these difficulties, instead of compressed air I used 

 superoxygenated air, and adapted slightly the apparatus set up in 

 my laboratory by my two assistants, MM. Jolyet and Regnard, an 

 apparatus which is both a simplification and an improvement of 

 the Regnault and Reiset apparatus. 



Here is a short description of it, which Figure 65 will allow the 

 reader to follow easily. 



The experimental animal is placed under the bell C, which is 

 provided with a thermometer t, a manometer m, and a little rubber 

 bag v, intended to offset the influence of outside modifications of the 

 barometric pressure, which must be taken into account in experi- 

 ments which may last several days. 



