Y14. ANIMALS AND VEGETABLES THz. 
not only where the point of the needle or edge 
of the inftrument touches, but far beyond it; and 
the vibration continues fome time, though the 
ftimulus which occafioned it is removed. Hav- 
ing taken a frog.on the point of death from a 
clofe veflel,—I will not fay the mufcles retained 
their irritability as. in a ftate of health, or that 
the approach of death did not weaken it,—but I 
will affirm, that the vibration and contraétion of 
the thighs, when cut and pricked,. re-appeared, 
and even continued. after the animal was entirely. 
dead. 
I abandoned the idea of loft mufcular irritabi- 
lity: and, after deep reflection, it has appeared 
to me that the nervous fyftem is the part on which 
the exhalations act.. And here are the reafons 
which have fuggefted that opinion ;. they are fub- 
mitted to the judgment of the philofophic reader. 
Convulfions commonly precede and attend the 
death of our animals: they are clearly manifeft 
in frogs. Sometimes the whole body is convulf- 
ed, but particularly, and more violently, the 
jimbs ; and in thefe convulfions they die. As 
they refift death longer in winter, the convulfions 
alfo continue longer. If taken from the veffel 
before death, it appears that the feat of fenfation 
has fuffered. They are fluggifh and. motionlefs ; 
nor do they change their place when {timulated, 
though. agitation is evident ; the conyulfions re- 
appear 5. 
