46 



Lewis and Clarke on the Cortical Lamination [Jan. 24, 



pathology. The scheme (Plate 3) appended to this paper represents 

 the distribution of these cells as determined from a thorough micro- 

 scopic examination of the left ascending frontal, and two npper frontal 

 convolutions of eight human brains, in all of which the arrangement 

 of these cells was remarkably uniform. 



The broad upper extremity of the ascending frontal convolution, 

 limited above by the longitudinal fissure and below by the lower line 

 of origin of the first frontal, was found to present two large groupings 

 of these cells. The first group (fig. 1, A — D) includes some of the 

 largest cells in this formation, and is distributed over the posterior or 

 parietal aspect of the gyrus adjacent to the ascending parietal convo- 

 lution. This group disappears towards the summit of this lobule, so 

 that the anterior or frontal half of a section usually shows none of 

 these cells present. 



Tig. 1. — Left ascending frontal and two upper frontal convolutions, seen from above. 



The letters refer to the parts from which sections figured in the scheme 

 were taken. 



The second group (fig. 1, E — G) apipears near the lower point of 

 origin of the first frontal, and is found along the frontal aspect at this 

 point — none being found posterior or along the parietal side. The 

 first group referred to occupies the upper two-thirds of this portion of 

 the ascending frontal, and limited almost exclusively to the aspect 

 adjacent to the ascending parietal, corresponds to the areas 2 and 4 in 

 Ferrier' s drawings.* In the scheme several sections through this area 

 (Plate 3, A — D) represent the exact number and distribution of these 

 cells at different levels from, above downwards. The lower group 

 (Plate 3, E), which takes a position forwards near the first frontal, 

 appears to correspond closely to another motor area (No. 5 of Ferrier). 

 The cell-groupings here are entirely on the frontal half of the convo- 

 lution, but at slightly lower levels, as at E and Gr they are observed 

 to spread over the vertex of the gyrus and appear at its posterior 

 aspect (Plate 3, F — Gr). 



The portion of this convolution intervening between the two upper 



# " The Functions of the Brain." By Dr. Ferrier. Figs. 63 and 65. 



