STRUCTURE OF THE LOBES OF THE CEREBRUM. ,385 



all directions (Kolliker). Seen in section they do not form by 

 themselves a definite layer ; on the other hand, as Arndt has 

 remarked, the presence of connective tissue, the fibres of which 

 run parallel to the surface, forms a dirty opaque border only 

 slightly stained by carmine, on the extreme margin of the 

 cortical layer. This thin medullary lamina is developed in the 

 gyrus uncinatus (Hakenwindung) into the far thicker stratum 

 reticulare, and, as is clearly the case there, so probably every- 

 where, is composed of cell processes directed outwards. Distri- 

 buted throughout the entire thickness of the outermost cortical 

 layers are irregularly angular nerve corpuscles with branched 

 processes, which are recognized as such by the well-founded 

 criterion of Deiters, that, namely, of exhibiting at the first 

 glance a relatively considerable proportion of protoplasm. 



Bearing in mind the manifold ramification of the processes 

 that can be exhibited by careful research, and the frequency 

 of the anastomoses demonstrated by Arndt and Besser to 

 occur between the processes of the cells of the cortex in certain 

 cases, and which we may fairly conclude to be present in all, 

 we shall be led to admit the existence of a nerve-fibre network 

 imbedded in the grey matrix, and forming its third diffused 

 morphological constituent. From what point of view such a 

 general anastomotic coalescence in the territory of origin of 

 the nerve medulla harmonizes with the phenomena of iso- 

 lated conduction has been already mentioned at p. 368. In 

 order to bring to a conclusion the preceding facts respecting 

 the general nature of the grey cerebral substance, it may 

 here be remarked that the nerve corpuscles are present as 

 sharply defined elements in the grey fibre network of the cortex 

 of the cerebrum at latest in the fifth month of embryonic 

 development (Arndt). They are unmistakably recognized as 

 persistent elements, by the parallelism of their axes with the 

 radial system of fibres, which (fig. 234, 3) is so characteristic 

 of the cortical substance. 



Notwithstanding his being able to recognize the cells at so 

 early a period, Arndt finds it possible to agree with Besser 

 that at the time of birth the nerve corpuscles have retrograded 

 into the transitional form of nuclei, with an ill-defined network 

 of branches; and that the central part of this network ulti- 



VOL. II. C C 



