The vascularity of the cerebral cortex of the albino rat

The work upon which the present paper is based is an extension of that previously reported by the writer ('20).I n the former publication an account was given of the relative vascularity of various parts of the spinal cord, brain stem, and cerebellum of the albino rat, and this account is extended in the present communication to include the cerebral cortex of the same animal.I n such a connection, there comes up for consideration not only the richness of the capillary supply of the cerebral cortex as compared with that of the parts previously studied, but also the relative vascularity of the various regions into which the cortex has been divided by physiologists and histologists.Also, little, if at all, behind these problems in interest comes the question of the conditions in the various layers which characterize the cortex.The more important accounts of the cortical localization in rodents, in so far as they are based upon histological studies, are reviewed by Sugita in his paper ('17) on the growth in thickness cf the cortex.He also correlates the various regions in which his measurements were made with the detailed description by Fortuyn ('14) of the conditions in the Norway rat and with the anatomico-physiological terms of Brodmann ('09) Sugita found the cortex of the albino rat, as Fortuyn had found that of the Norway rat, to be divisible, in typical localities, into five Jaminae.His description of these laminae is as follows:The cerebral cortex of the albino rat has five cell layers if a typical locality be taken.The most external layer is the lamina zonalis (I), which has a few scattered glia-cells.Under this, there is the lamina