ATMOSPHERIC PRESSURE AND LIFE. 



327 



cock, and in a moment bring the animal back to normal pressure ; he 

 turns around two or three times and drops dead. Were I to make an 

 autopsy now, I should find the heart and the great vessels full of gas ; 

 so great is the amount, that once I drew off fifty cubic centimetres of 



Fig. 5. 



gas from the vessels of a cat decompressed in this way. This gas is 

 nitrogen with a little carbonic acid. 



The process is as follows : The animal by breathing compressed 

 air charges its blood with air in the proportions indicated by physical 



