TREATMENT OF DECOMPRESSION SYMPTOMS 249 



cavities surrounded by compressed and flattened cells. These 

 cavities are especially evident in the liver and central nervous 

 system. The bubbles set free in the blood-vessels run together 

 at less resistant points, and the vessels become occupied here 

 with columns of corpuscles and there with long bubbles of gas. 

 Bubbles are set free in all the connective tissue spaces and 

 especially in adipose tissue. The alimentary canal becomes dis- 

 tended with gas. We have never seen bubbles actually within 

 a muscle, nerve, or other cell ; the cells are not torn but compressed 

 by the bubbles. The longer the exposure to compressed air the 

 more completely do the tissue fluids become saturated with 

 dissolved gas. 



THE TREATMENT OF THE DECOMPRESSION SYMPTOMS 



As we have seen in the experiments on the frog and bat, the 

 bubbles of air, which develop in the capillaries, pass back into 

 solution on a rapid reapplication of the pressure. 



We have tried this in the case of larger animals. 



A rabbit was kept under a pressure of 8 atmospheres of air 

 for hours and was then quickly decompressed. In a minute or 

 so the rabbit developed typical decompression symptoms (i.e. fell 

 on side and limbs showed tetanic convulsions). The pressure 

 was now quickly reapplied up to about +5 atm. by emptying 

 a large cylinder of compressed air into the chamber. The 

 symptoms, however, remained unabated and the rabbit soon 

 died. It was evident, therefore, that for the reapplication of 

 pressure to be of any avail, the pressure must be very quickly 

 re-established, and no time be given for the air-bubbles to tear 

 up and damage permanently the nervous tissues, or to produce 

 stasis of the circulation for too long a period. 



We therefore repeated the experiment, with the modification 

 that the pressure was more quickly reapplied. 



A cat and a rabbit were subjected to an air pressure of 

 8 atm. for 4 hours. Decompression was effected to zero in about 

 five seconds, and as quickly as the taps could be opened (about 

 five seconds) a large cylinder of compressed air was delivered 

 into the chamber, thus raising the pressure to 75 atm. in about 

 2 minutes. 



