The cerebral arteriovenous oxygen difference has been studied not only in normal subjects but in psychotic patients and in mentally defective persons. In the present investigation these studies were extended in order to determine the effect of age and mental deficiency on the cerebral arteriovenous oxygen difference. The subjects were normal babies less than 2 weeks of age and mentally deficient persons 6 to 55 years of age who belonged to the undifferentiated group, i. e., persons apparently normal except for their low intelligence.
METHOD
Samples of blood were collected from the femoral or the brachial artery and the internal jugular vein. The method for the collection of the venous blood was that of Myerson, Halloran and Hirsch,1 the needle being inserted in the internal jugular vein close to its point of exit from the cranial cavity through the jugular foramen. When the fontanel was patent, blood was drawn