Sudden Changes in Pressure 861 



B. Experiments Made on Rats. 



Experiment DXVI. August 9, 1871. Rat. Seltzer water receiver. 

 9:25, placed at 7 atmospheres. 10:10, pressure fell to 6V2; the 

 animal is rolled up in a ball, with hair bristling; respiratory rate 75. 



1 open the large cock suddenly; the animal arouses immediately, and 

 does not seem to be in pain. 



Experiment DXVII. August 10. Same animal, same apparatus. 



4:10, placed at 6 atmospheres. 5:25, respirations difficult, dicrotic; 

 the animal is lying curled up on the bottom of the vessel. Took sample 

 of air, which contained 5.2% of CO,. Tension: 5.2 x 6 = 31.2. The 

 pressure then falls to 5V 2 . I open the large cock suddenly. The animal 

 almost immediately stands up on his feet, and seems quite well. 



Experiment DXVI II. August 12. Same animal, same apparatus. 



At 4:15, placed at 6V2 atmospheres. The apparatus leaks; at 6 

 o'clock, the pressure is 4V 2 atmospheres; the animal is very sick. I 

 take a sample of air, which contains 6.1% of CO,. 



Tension: 6.1 x 4.5 = 27.4. I open the cock wide; the rat does 

 not recover immediately, but he is well the next day. 



All the experiments reported next were made in the large 

 cylinder of sheet-iron pictured in Figure 33. The large cock which 

 is opened suddenly is the one lettered c: 



Experiment DXIX. May 24. Two rats in the large cylindrical 



apparatus (experiment made before the Committee of the Institute). 



They are taken to 8V2 atmospheres; the decompression is made in 



2 minutes. The rats run about when taken from the apparatus; a 

 few minutes after, they become paralyzed and die. Gas is found in 

 the whole venous system. 



C. Experiments Made on Rabbits. 



Experiment DXX. June 22. Rabbit. 



Taken to 8 atmospheres. Decompressed in 3 minutes. Ears bright 

 red; no symptom either immediate or later. 



Experiment DXXI. November 7. Two rabbits. 



Taken to 7 atmospheres. Decompressed in 2V2 minutes. No 

 symptoms. 



Experiment DXXII. November 10. Same animals. 

 Taken to BVs atmospheres; decompressed in 2V4 minutes. 

 No symptom either immediate or delayed. 



Experiment DXXIII. November 15. Rabbit. 



Taken to 6V2 atmospheres. Decompressed in 4 1 2 minutes. No 

 effect. 



D. Experiments Made on Cats. 



Experiment DXXIV. May 23. Male cat, extraordinarily vigorous 

 and wild. Taken to 10 atmospheres. Sudden decompression. Leaps 



