Three Chinese adult brains were selected for the study of the histological struc-ture of the cerebral cortex of the Broca's area with a comparison between thecorresponding parts of both hemispheres.Nissl's staining,Weil's and Golgi's techniqueswere employed for the microscopic examination.The results are as follows:(1)The thickness of the cortex of the Broca area in the specimen stained byM?lligan's method is in the range of 3.5 mm to 5.0 mm.(2)The thickness measurements of the six layers in the thickest cortex are 0.17mm(Ⅰ),0.11 mm(Ⅱ),1.06 mm(Ⅲ～Ⅴ),1.52 mm(Ⅵ)and in total 2.86 mm inthe left hemisphere,and 0.15 mm(Ⅰ),0.10 mm(Ⅱ),0.87 mm(Ⅲ～Ⅴ),1.50 mm(Ⅵ),and in total 2.62 mm in the right hemisphere respectively.(3)The ratio of height/width of pyramidal cells in the second layer are 16.84?4.46 ?m/9.50?2.32 ?m in the left hemisphere and 15.60?4.56 ?m/8.88?2.03 ?min the right hemisphere respectively.(4)The ratio of the height/width of the pyramidal cells in the fifth layer are56.90?7.99 ?m/14.79?3.26 ?m in the left hemisphere and 49.80?9.08 ?m/14.67?7.88 ?m in the right hemisphere respectively.There is a very significant difference(P0.05)betweenthe widths of the pyramidal cells of the two hemispheres.(5)Within an area of 6400 ?m~2 of a section 10 ?m in thickness,in the firstmolecular layer,there are 13.0 cells in the left hemisphere and 11.7 cells in the righthemisphere respectively.(6)In this area all of the pyramidal cells are not exceeding 60 ?m in height,hence there is no Betz cells.In addition to the large population of pyramidal cells,there are cajal horizontal cell,Martinotti cells,fusiform cells,etc.