7i 
on which the action of the heart depends , &c. 
carotid artery was found beating. On dividing it, blood of 
a much darker colour than in the former experiment was 
thrown out copiously per saltum. 
Exp. 6. A rabbit was rendered insensible by a blow on the 
occiput, and artificial respiration maintained. The spinal mar- 
row from the base of the skull to the beginning of the dorsal 
vertebras was removed, and a hot wire forced through the 
remaining part of the spine. The carotid artery was then 
found beating, and on dividing it florid blood rushed out with 
great force per saltum. 
Exp. 7. This experiment resembled the last, except that 
the spinal marrow, instead of being partly removed, was 
wholly destroyed by a hot wire, and artificial breathing was 
not performed previous to opening the carotid, from which 
dark coloured blood flowed per saltum. We then inflated the 
lungs, and arterial blood soon began to flow copiously from 
the vessel, and appeared like a florid stream mixing with the 
dark coloured blood which had previously come from it. 
This experiment was repeated in the same manner, and with 
the same result. 
Exp. 8. In this experiment the rabbit was rendered insen- 
sible, but not motionless, by the blow on the occiput, so that 
the breathing still continued. The spine was opened, and 
the spinal marrow destroyed, as in the preceding experiment. 
The wire was used very hot. On introducing it through the 
spine into the brain, the breathing immediately ceased. The 
femoral artery was laid bare about two or three minutes after 
respiration had ceased. The beating of the artery was evi- 
dent. On opening it, a dark coloured blood flowed from it 
freely. We now had recourse to artificial respiration. When 
