Extra-Ventricular Formation of Cerebrospinal Fluid

　By the use of subarachnoid-subarachnoid perfu-sion method, a quantitative measurement of the amount of CSF formed in the subarachnoid space has been made. These experiments confirmed previous results indicating that about 40% of cerebrospinal fluid was formed in the subarach-noid space and about 60% in the ventricles of the dog. Other data from cats and patients which indicate that about the same fractional formation of CSF is probably and generally true for all species.