1. Ten experiments, each using two dogs, were performed to evaluate the effect of chemoreceptor and baroreceptor activity on the cerebral circulation.
2. The carotid bifurcation areas were vascularly isolated bilaterally and perfused with arterial blood from a second animal.
3. Bilateral vagotomy interrupted stimuli from the aortic group of receptors.
4. Administration of 5% carbon dioxide to the donor animal resulted in an increase in cerebral (cortical) blood flow in the recipient.
5. A change in the arterial perfusion pressure from the donor resulted in a reciprocal change in the cerebral blood flow of the recipient. These changes were abolished by sectioning the sinus nerves.