gem Mr. Brqdie on the different Modes 
of the heart had never ceased ; as the circulation of the blood 
was kept up by artificial respiration for more than an hour 
and twenty minutes after the poison had produced its full 
effects ; and as during this time the usual changes in the 
colour of the blood took place in the lungs ; it is evident that 
the functions of the heart and lungs were unimpaired: but 
that those of the brain had ceased, is proved, by the animal 
having continued in a state of complete insensibility, and by 
this circumstance, that animal heat, to the generation of which 
I have formerly shewn the influence of the brain to be neces- 
sary, was not generated. 
Having learned that the circulation might be kept up by 
artificial respiration for a considerable time after the woorara 
had produced its full effects, it occurred to me that in an ani- 
mal under the influence of this or of any other poison that 
acts in a similar manner, by continuing the artificial respira- 
tion for a sufficient length of time after natural respiration 
had ceased, the brain might recover from the impression, 
which the poison had produced, and the animal might be 
restored to life. In the last experiment, the animal gave no 
sign of returning sensibility; but it is to be observed, i. That 
the quantity of the poison employed was very large. 2. That 
there was a great loss of animal heat, in consequence of the 
temperature of the room being much below the natural tem- 
perature of the animal, which could not therefore be considered 
under such favourable circumstances as to recovery, as if it 
had been kept in a higher temperature. 3. That the circula- 
tion was still vigorous when I left off inflating the lungs, and 
therefore it cannot be known what would have been the re- 
sult, if the artificial respiration had been longer continued. 
