[ 9§ ] ' 
Experiment XCVIII. 
Nitrous air is more noxious to the 
conftitution of frogs, than that of which 
we have been fpeaking. 
( , f k 
They are fcarcely plunged in it, fcarcely 
make one infpiration before one fees them 
linking againft the veffel, ftruggling and 
tumbling over in the mod: confufed man¬ 
ner. In the midfl of thefe violent con- 
vulfions, they fall as it were into a fainting 
fit. Some few minutes after, their tor¬ 
ments begin again, are fucceeded by a 
kind of total defertion of life. Thefe 
alterations take place feveral times, and at 
length give way to a tranquil death. In 
thefe frogs the motion of the heart is com¬ 
monly deftroyed, or if it retains fome 
palpitations, they are feeble, and at long 
intervals. 
This vjfcus is found much difiended, 
and filled with very black blood. The 
mufcles 
