Abstract
15 mum labelled microspheres were used to determine the effect of stimulation of the cervical sympathetic chain on blood flow through different parts of the brain and through some extracerebral tissues of the head in monkeys. Unilateral stimulation at 10 Hz for one min caused mean reductions in blood flow through the masseter muscle, the parotid gland, and the tongue of 76-94 percent in 9 monkeys, while in the same animals there were no convincing effects on regional cerebral blood flow.