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

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