2 Transactions of the 



pass vertically toward the white substance. The pointed process 

 attains, according to the size of its ganglionic body, a length of 

 from tVo to YoV mm. In its more or less serpentme course it 

 ^ves off a number of small lateral branches, which soon termmate 

 in the above-mentioned fibriUous nervous network of the granular 

 substance. I have never seen this process terminate m a dark- 

 borderal nerve fibre. From the lateral process, a dark-bordered 

 nerve fibre always arises ; it attains a considerable length, and its 

 course is more or less horizontal. A direct communication between 

 two ganglionic bodies by means of" these fibres I have never seen ; 

 in some cases, however, I have observed them dividing into two 

 branches, the ramifications of which ended in the terminal network. 

 From the basal processes, the nerve fibres of the white substance 

 arise. On ganglionic bodies of medium size, two of these processes 

 are ordinarily seen, one of which is converted into a nerve fibre, 

 while the other divides dichotomously. One of the branches result- 

 ing from this division forms also the axis cylinder of a nerve fibre, 

 while the other subdivides into finer branches, which terminate in 

 the network. In the larger ganglionic bodies, even the first basal 

 process divides and gives rise to two axis cylinders. 



In the upper strata of the cortical layer a considerable number 

 of smaller ganglionic bodies of a more triangular or quadrilateral 

 form are met with. Their delicate processes run about in the 

 same direction, and terminate in the same manner as those of the 

 larger bodies just mentioned. 



The nerve fibres of the white substance, arising from the basal 

 processes, leave the grey matter in the form of bundles, composed 

 of about eight to ten, or even more nerve fibres of different thick- 

 ness. Generally, two or three of the fibres, of from -^^-is to ^^o mm. 

 in diameter are met with in each bundle; the rest are finer fibres, 

 of about ^^ to si^ mm. in diameter. One portion of the finer 

 fibres appears to arise from the smaller ganglionic bodies of the 

 upper strata, but another arises directly from the terminal nervous 

 network. At first, the bundles of nerve fibres are separated from 

 each other by considerable interspaces ; but as others arise from 

 the ganglionic bodies situated below, the interspaces become more 

 narrow, until, at the border of the white substance, they are 

 entirely lost, so that the bundles come to lay contiguous to each 

 other. 



In tracing the different nervous elements, imbedded in the 

 granular substance of the cortical layer of the cerebrum, from the 

 surface toward the white substance, we first meet with the exceed- 

 ingly fine, felt-like, fibrillous neuroglia, covering the surface and 

 extending throughout the whole cortical layer to the white sub- 

 stance. Directly under the neuroglia, in the uppermost stratum 

 of the cortical layer, a considerable number of fine dark-bordered 



