REMARKS ON SPINAL GANGLIA AND NERVE-FIBRES. 377 
‘The nuclei already stained by the hematoxylin are made of 
a richer colour, while the protoplasm surrounding them is 
much bluer than the nuclei themselves. In the cerebellum 
the effect is particularly good, the medullary substance being 
of a rich purple, and the cortical substance of a pale blue, 
but showing the cells with remarkable clearness. 
Some REMARKS on SPINAL Ganoiia and NERvE-FIpREs. 
By Jerem1aH McCarrny, F.R.C.S. Eng., Lecturer on 
Physiology at the London Hospital Medical College. 
(With Plate XXII.) 
I HAVE recently, in examining preparations of spinal 
ganglia, observed some structural details which were new to 
me, and to which I wished to direct attention. But, on con- 
sulting the abundant literature on the subject, I find that 
nearly all the points have been anticipated by other observers. 
Still, as the mode of preparation which I have used brings 
out these structural details very clearly, and as my investiga- 
tions were made in ignorance of the recent discoveries, my 
independent corroboration of them may not be uninteresting 
to readers of this Journal. 
I have used as material the spinal ganglia of dogs, and 
prepared them in the following manner :—The animal having 
been killed, the gangha were at once taken out and kept in 
2 per cent. solution of mono-chromate of ammonia for three 
weeks, and, the solution having been changed once or twice 
during that time, were then transferred to methylated 
spirit. After a few days longer they were ready for section. 
The sections were stained with hematoxylin, and were finally 
mounted in Canada balsam solution. Sections so prepared 
form very beautiful microscopic objects, as there is no 
shrinking or disturbance of the relation of the tissues. 
The surface of the ganglion is covered by a thick layer of 
fibrous tissue, which contains numerous blood-vessels and a 
little fat. From this processes pass into the ganglion, and, 
there ramifying, form a delicate meshwork for the nerve- 
fibres or blend with the capsules of the ganglion-cells. The 
ganglion-cells are very unequal in size, the largest being five 
or six times the size of the smallest, and between these ex- 
tremes are numerous gradations.! These cells are arranged 
1 With Hartnack’s No. 2 micrometer ocular, and No. 8 objective, some 
of the largest cells measure 0:080 m. in diameter, some of the smallest, 
0:014 m. 
