“NERVOUS CENTRES. (Tuerr Microscoprcat Anatomy.) 
freely intermingle. The anterior and posterior 
yramids and the restiform bodies consist, at 
Sst in great part, of longitudinal fibres, but the 
remainder of the fibrous matter appears to be 
made up of transverse or oblique fibres. Most 
of these are doubtless connected with the roots 
of the many nerves which arise from the me- 
. dulla oblongata. Stilling refers to special ac- 
cumulations of vesicular matter connected with 
709 
the roots of each nerve, and which probably 
form its proper origin. These contain large 
vesicles. It is impossible to give an exact in- 
terpretation to all the parts which are seen by 
his method of examination, imperfectly defined 
as they are from the use of such low mag- 
nifying powers. It would be waste of time 
and space to do more than refer to the repre- 
sentation given by Stilling ( fig. 397) of the 
Fig. 397. 
4 
WP 
a, Rathi: , 
" Pransverse section of the medulla oblongata through the lower third of the olivary bodies. (From Stilling. ) 
ii Magnified ten diameters. 
Ra; anterior fissure; b, fissure of the calamus scriptorius; c¢,raphé; d, anterior columns; e, lateral 
_ columns; f, posterior columns; g, nucleus of the hypoglossal nerve, containing large vesicles; h, 
sb nucleus of the vagus nerve ; i, i, gelatinous substance ; k, k, roots of the vagus nerve ; I, roots of the 
_ hypoglossal, or ninth nerve ; m, a thick bundle of white longitudinal fibres connected with the root of 
the vagus; n, soft column ( Zartstrang, Stilling); 0, wedge-like column ( Keelstrang, Stilling) ; p, trans- 
_ yerse and arciform fibres ; \g, nucleus of the olivary bodies; r, the large nucleus of the pyramid ; 
_ 8,8,8, the small nuclei of the pyramid; wu, a mass of grey substance near the nucleus of the olives 
Nebenkern ) ; 
structure, as viewed by a magnifying power of 
‘ten diameters. Nothing can be more true to 
re, so far as it goes, but its correct explana- 
ion must be sought for by diligent investigation 
with high powers. Numerous bloodvessels pe- 
netrate the central matter of the medulla, and 
‘no doubt many of the lines, which Stilling 
“tas te to represent fibres, «are in reality ves- 
se petal to the grey matter. 
é mesocephale has very much the same kind 
of structure as the medulla oblongata; trans- 
verse fibres (those of the pons) at its anterior 
part, longitudinal ones just behind these (pyra- 
mids), with vesicular matter freely intermixed. 
Its posterior part is the same in structure as 
the optic thalamus, and consists of numerous 
fibres with an abundant quantity of grey matter. 
The inferior layer of the crus cerebri is purely 
fibrous; its superior portion is identical in 
| u,q,7, are traversed by numerous fibres passing in a transverse semicircular 
direction ; v, w, arciform fibres; x, grey matter near the root of the vagus. 
structure with the optic thalamus, and the locus 
niger contains large caudate nerve-vesicles, 
with a considerable quantity of pigment con- 
tained in them. 
Microscopic investigation has as yet thrown 
no light on the direction and connections of the 
fibres of the cerebrum or cerebellum. What is 
known upon these points is derived from coarse 
dissection. The tubular fibres of which the 
white matter is composed, appear to be dis- 
food on different planes, and perhaps inter- 
ace with each other, so as to render it difficult 
to isolate any plane to any great extent. This 
arrangement is more obvious in the cerebellum 
than in the cerebrum. The grey matter of 
both these segments contains the ordinary ele- 
ments, caudate and spherical vesicles; but in 
the cerebellum those of the latter variety are 
much larger and more distinct than those which 
