ARCHITECTURAL CHANGES DUE TO GROWTH. 



247 



as regards the layers in question. The fibres were a 

 trifle more abundant in the occipital than the frontal 

 portions. The cortex of the dorsal surface was most 

 developed, that of the ventral least, and the mesal 

 surface was intermediate between these two. The 

 dorsal surface reaches full development first, and the 

 other surfaces follow in the order named. The develop- 

 ment is often very local, and there is by no means a 

 uniform character common to large areas. 



TABLE 56. GIVING THE THICKNESS OF THE CORTEX AND ITS 

 SEVERAL LAYERS IN MILLIMETERS. (Kaes.} 



The letters refer to Fig. 47. The most striking points in the 

 table are the influence of locality and age on the thickness of 

 these layers. 



AVERAGE THICKNESS OF THE ENTIRE CORTEX AND ITS LAYERS, IN MILLIMETERS. 



The specimens showed an increase in the II and III 

 layer by the addition of new fibres and a compacting of 

 the zonal fibres, together with those forming the layers 

 of Baillarger (G), outer or (E) inner, a compression which 

 in the layer first named may possibly be associated 

 with the loss of fibres. These facts are summarised in 

 the accompanying table (56). 



