CD 



KEW YOkK 

 BOTANICAL 



THE \^RDe3^ 



MONTHLY MICROSCOPICAL JoSmL. 



JULY 1, 1874. 



I. — Synojysis of the PrincijMl Facts elicited from a series of 

 Microscopical Researches ujoori the Nervous Tissues. 



By Dr. H. D. Schmidt, of New Orleans, La. 



(Bead before the Royal Microscopical Society, Jane 3, 1874.) 



1, The ganglionic bodies of the spinal marrow and brain repre- 

 sent plexuses of nervous fibrillin, which are continuous with the 

 fibrillae of the processes and axis cylinders arising from them. 

 Each plexus, thus formed, embraces a nucleus which is distinguished 

 by a double contour representing its wall ; it contains a large 

 nucleolus and a great number of small granules. The nucleolus is 

 also distinguished by a fine, sharply-defined double contour, and 

 filled up by granules. In the large ganglionic bodies of the spinal 

 marrow, it contains besides the granules two clear bodies of a 

 reddish lustre ; the one of these is never wanting, and is distin- 

 guished by its size, amounting to « io- nim. in diameter, and also by 

 its brightness. It appears in the form of a vesicle with a dark 

 granule in its centre. The other is usually somewhat smaller, and 

 frequently absent. In many cases, in addition to the nucleolus, a 

 lew smaller ones are observed, which, however, contain no ghmmer- 

 ing vesicles, but are only filled with granules. 



2. The Cortical Layer of the Cerebrum* — The nervous portion 

 of this consists of numerous ganglionic bodies of different form and 

 size, and of vertically or horizontally-running nerve fibres arising 

 from them ; further, of a fine granular substance, lodging a network 

 of fine granular fhrillse, and also a considerable number of free 

 nuclei. The typical form of the greater portion of the ganghonic 

 bodies in this portion of the brain resembles a more or less spindle- 

 shaped tuber, from the sides of which a number of greater or 

 ^ smaller conical processes arise ; the whole body appears, therefore, 

 '^ in a thin section in the form of a triangle or pyramid. The average 

 ^^ number of the processes is four or five. One of them, the pyramidal 

 ■"^ or ])ointed process, takes a vertical course toward the surface of the 

 C_5 cerebrum ; another, sometimes two, the lateral processes, pass in a 

 ^ more or less horizontal direction ; and the rest, the basal processes, 



* The description relates mainly to the convolutions of the convexity of the 

 hemispheres of the cerebrum of man. 



VOL, XII. B 



