the Foramina Thehesii of the Heart . 109 
that this could not be done, without greatly torturing the ani- 
mal, I did not choose to prosecute so cruel an experiment. 
Young animals, indeed, retain their irritability for a consi- 
derable time, so that they move long after they have been 
plunged beneath water ; and may even, on this account, reco- 
ver after they are taken out. But the manner in which Buf- 
fon has related his experiment seems to imply, that the circu- 
lation of the blood, and other functions of life, were continued 
after the animals had been excluded from the air. I am con- 
vinced that the poor dog who was the subject of my experiment 
would have been beyond recovery in a few minutes. 
, Those animals who are accustomed to remain long under 
water, probably first fill their lungs with air, which may, in a 
partial manner, oxygenate their blood during their submersion. 
The true statement of this subject may probably be, that the 
circulation of venous blood will destroy most animals in a very 
short space of time ; but that custom may enable others to en- 
dure it, with very little change, for a longer period. 
