286 Messrs. L. Hill and M. Greenwood, Jun. [Jan. 26, 



(2) Three rats were exposed to + 75 lbs. 2 for three-quarters of an hour. 

 Decompression time, 4 seconds. All three were paretic. The peritoneal gas 

 of one contained — 



r C0 2 2*2 per cent. 



\ 2 28-3 



Ur 2 69-5 



(3) Three rats exposed for one hour to +75 lbs. 2 . Decompression in 

 3 seconds. Two rats were dead, the third moribund. Peritoneal gas — 



f C0 2 6'7 per cent. 



1 2 26-7 



Ln 2 66-6 



(A sample of the chamber air contained only 75 per cent. 2 , showing that it 

 had not been completely washed out at the commencement of the experiment, 

 since the gas in the cylinder used in this experiment contained 87*3 per 

 cent. 2 .) ' 



(4) Experiment, 12.12.06— 



11.55 A.M. — Six rats and six mice were placed in the pressure chamber, 

 which was washed out with oxygen and then raised to + 75 lbs. 2 . 



12.0. — Two of the mice convulsed. 



12.5. — One rat exhibits a twitching of limbs, all the mice affected. 



12.20. — All the rats affected, one convulsed. 



12.35. — Decompression in 4 seconds. Several rats immediately thrown 

 into convulsions. 



On opening the chamber, four mice were found to be dead, two others 

 affected, one of them dying in a few minutes. Of the rats, one was dead, 

 two convulsed, three moderately affected. Of these five, three died, one 

 was killed, and the fifth recovered. A sample was collected. One mouse 

 (dead) yielded a good deal of gas, one rat (dead) very little, and one rat (killed 

 for analysis) a considerable amount. 



The analysis gave — 



f C0 2 and 2 67'9 per cent. 



IN 2 32-1 



These experiments are not sufficiently numerous to permit of very exact 

 statements being made, but they seem to show that free oxygen is liberated 

 during decompression if the animal exhibit symptoms of oxygen poisoning. 



The onset of convulsions immediately after decompression, mentioned in 

 the above account, is very suggestive, and may well have been due, to the 

 sudden liberation of gas bubbles acting on the already poisoned tissues. 



