THE QUANTITATIVE HISTOCHEMISTRY OF THE CEREBRAL CORTEX—I. ARCHITECTONIC DISTRIBUTION OF TEN CHEMICAL CONSTITUENTS IN THE MOTOR AND VISUAL CORTICES *

THE development of quantitative methods for the measurement of chemical and enzymatic tissue constituents in samples of tissue weighing less than 10 p g has made possible the study of the amount and localization of these constituents at rather precise locations in the brain (ROBINS and SMITH, 1953; LOWRY, ROBERTS, LEINER, Wu, FARR, and ALBERS, 1954; POPE, 1952). By utilization of these methods, it is possible to study the chemical and enzymatic architectonics of the cerebral cortex. In this report, the results of a study of the distribution of dry weight per unit volume, protein, total lipide, cephalins, lecithins, sphingomyelins, total sphingolipides. non-phosphorus-containing sphingolipides, total phospholipides, cholesterol, and number of cells per unit volume in each histologically defined layer and sublayer of the motor cortex and visual cortex of the monkey are presented. In thc accompanying papers, studies of some of the enzymatic constituents of these layers ( R O B I ~ S , MITH, EYDT, and MCCAMAN, 1956) and of analyses at 50 p intervals compared with those by architectonic layers throughout the depth of the two cortices (ROBINS. MITH, and EYDT, 1956) are reported.