236 ANNUAL RECORD OF SCIENCE AND INDUSTRY. 



receiver be closed, however, the animal dies with asphyxia. 

 The composition of the air in which animals die varies with 

 the pressure. Birds can be kept living when the pressure is 

 reduced below eighteen centimetres. Mammals can sustain 

 a reduction to twelve centimetres, but under these circum- 

 stances their temperature diminishes by several degrees. 



Cold-blooded, and some new-born animals, can sustain a 

 still greater diminution of pressure. The less the pressure 

 at which the animal suffocates, the more oxygen and the less 

 carbon are found in the remaining air. The animals which, 

 at the same pressure of the atmosphere, leave most oxygen 

 that is, form least carbonic acid are falcons, owls, and grown 

 cats ; then come the sparrows, and afterward frogs and new- 

 born cats. 18 C, August 15,1871,517. 



BEET ON THE INFLUENCE OF INCREASED ATMOSPHERIC 



PRESSURE. 



We have already referred to the observations by 31. Bert 

 upon the effects produced upon animals by diminished atmos- 

 pheric pressure, and we now have a report from him upon the 

 phenomena presented when this pressure is increased. The 

 animals experimented upon were sparrows, rats, and frogs, 

 placed in a vessel of the capacity of one quart, in which about 

 fifteen minutes were required to obtain a pressure of nine 

 atmospheres. This increase, however rapidly produced, ap- 

 peared to exercise scarcely any effect upon the animal, the 

 respiration only becoming feeble at about the time when the 

 phenomena peculiar to asphyxia commenced, the animal ex- 

 piring with convulsions, with an internal temperature of S0 

 to 92 Fahrenheit that is to say, scarcely above that of the 

 surrounding air. After death,under a pressure greater than 

 two atmospheres, very red blood was found not only in the 

 arteries, but in the veins ; and with a pressure above five at- 

 mospheres numerous bubbles of gas appeared in the right 

 cavities of the heart, which were not disengaged by the re- 

 turn to the normal pressure. Sparrows could not bear with 

 impunity a pressure of over seven or eight atmospheres, and 

 in some instances, if the asphyxia was very decided, they 

 seemed to perish suddenly by an abrupt decompression. In 

 tliis case they were found to have free gas in the right side 

 of the heart. 3 B, xix., September 7, 1871, 524. 



