Determination of the number of cells within the cerebral cortex has been of great concern to anatomists as well as to pathologists for the past fifty years. Investigation of the cerebral cortex from the phylogenetic point of view also demands knowledge of the cell number in relation to the growth and evolution of the nervous system. Dubois ( '30) expressed his belief that phyletic growth of the brain has occurred in "jumps" during which the number of nerve cells increased i n multiples of d% A numerical test, however, has never been undertaken. The latest attempt to link cortical cell number with the study of phylogeny of the cerebral cortex is a paper by Shariff ( ' 5 3 ) which deals with cell counts in the primate cerebral cortex.
During recent decades numerous authors have reported the presence of significant histopathologic alterations in the cerebral cortex of schizophrenics. Among the earlier investigators Alzheimer ( '10) reported localized disappearance of neurons of the outer layers of the cerebral cortex in individuals affected with mental illness. Similar local or diffuse changes were reported by Bouman ( '28) and Hechsts ( '33). Most recently Rowland and Mettler ( '49) made quantitative studies on the frontal cortex removed at operation from psychotic ' The author wishes to acknowledge the cooperation and support of Dr. Ralph Rossen, Superintendent of the Hastings State Hospital.