QUARTERLY CHRONICLE OF MICROSCOPICAL SCIENCE, 193 
cerebral cortex, breaking up into a number of minute 
nerve-fibres. 
The well-known large ganglionic cells discovered by 
Purkinje are described by Golgi as having ramifying proto- 
plasmic processes of extraordinary complexity, the ultimate 
destination of which he was unable to trace. The axis- 
cylinder process passes through the granule-layer into the 
nerve-fibre tract, and there gives off numerous fine processes, 
of which some bend back into the molecular or outer layer 
of the cortex. The elements of the granule-layer are mostly 
small ganglionic cells possessing an axis-cylinder process and 
numerous branched protoplasmic processes. They are usually 
one half or one third the size of Purkinje’s cells, that is, twenty 
to sixty mm. in diameter, but some attain almost to the dimen- 
sions of those cells. The fibres which pass into the granule- 
layer and bend outwards divide and ramify there in a very 
complicated manner, some of the minute fibres entering into 
connection with the small ganglion-cells of that layer. The 
nerve-fibres of this layer also, like those of the other layer, 
form loops, twists and knots, so that a system of great 
perplexity results. 
5. Variations in the Structure of the Spinal Cord.—F lech- 
sig (‘ Centralblatt,’ 1874, p. 561) describes variations in the 
spinal cords of infants born at full time, especially with 
regard to the continuation of the pyramids into the columns 
of the cord. 
6. Development of Nerves.—See ‘ Observations sur le dé- 
veloppement des nerfs périphériques chez les larves de Batra- 
ciens et de Salamandres,’ par Ch. Rouget (‘ Comptes Rendus 
Acad. des Sciences,’ 1874, p. 306 and p. 448). 
VIII. Organs of Sense.—l. Structure of the Olfactory 
Mucous Membrane.—Cisoff (‘ Centralblatt,’ 1874, p. 689) 
has reinvestigated this structure, in order to compare 
the original statements of Max Schultze with the con- 
flicting results of Exner (see ‘Quart. Journ. Mic. Sci.,’ 
1871, vol. xi, n. s., p. 800), and believes the differences 
to depend partly on the different methods employed. 
Exner described a _ sub-epithelial network of nerve- 
tissue, which was connected on the one hand with twigs of 
the olfactory nerve, on the other hand with both the epi- 
thelial cells and the “ olfactory cells’ of the surface. Cisoff 
affirms that the apparent connection of this network or the 
sub-epithelial tissue with nerve-fibres is illusory, and 
is only seen in osmic acid preparations. In_ sections 
of gold preparations the nerve-fibres are clearly seen 
passing through the sub-epithelial tissue into the epithe- 
