Sudden Changes in Pressure 889 



After the 10th injection (650 cc), the animal does not seem to be 

 in danger. At the 24th minute, injections are resumed, but this time 

 every minute. 



After the 17th injection (1100 cc), the animal groans, urinates, 

 stretches out its legs with force. The heart beats grow slow, the 

 respirations are very rare, and the animal dies at 3:55. Its temper- 

 ature dropped 1°. 



1 found the right heart full of foam, blood frothed with air, with 

 a large quantity of free air; it was present also in the venae cavae 

 and the pulmonary arteries. 



Numerous bubbles of air in the left heart and the cardiac arteries 

 and veins; there was none in the arteries of the limbs and the portal 

 •vein. 



In Experiment DLXXXII, a dog, which was small, it is true, and 

 sick, was killed by an injection of 14 cc. of air, while in Experi- 

 ment DLXXXV, it was necessary to go as high as 1100 cc. to kill 

 a large dog. These experiments, in short, show us as many differ- 

 ences for artificial injections of air into the veins as for the sort of 

 physiological injection which takes place during sudden decom- 

 pression. 



One of the most important elements to be considered in regard 

 to the appearance of morbid symptoms following decompression is 

 the length of the stay in the compressed air. This plays the prin- 

 cipal part, after the degree of compression and the speed of the 

 decompression. So, whereas for dogs decompressed immediately 

 after the desired degree had been reached there are no serious symp- 

 toms, as Table XVIII shows, before reaching 7 atmospheres, in Ex- 

 periment DLXIII, we see a dog dying quite rapidly after leaving 

 the apparatus in which the pressure of 6 atmospheres had been 

 maintained for 3V2 hours. Experiment DXV made on a sparrow is 

 still more remarkable. However, Experiment DLXIV shows us a 

 dog which had no symptoms after a stay of 4 hours under 5V2 at- 

 mospheres; but he had in his blood abundant bubbles of gas, and 

 was consequently under the threat of an imminent morbid attack. 



In conclusion, it is possibly interesting to note that aquatic ani- 

 mals are killed by sudden decompression for the same cause as 

 terrestrial animals and by the same mechanism. But it will no 

 doubt seem enough to report one experiment to support this state^ 

 ment which presents true interest in regard to the conditions of life 

 of these creatures: 



Experiment DLXXXVI. April 6. Eels "de la montee" (young), 

 transparent, subjected for two days to a pressure of 10 atmospheres 

 of air. 



2 o'clock, decompressed suddenly; emit from their mouths bubbles 

 of gas. 



