ioo PRACTICAL HISTOLOGY. 



THE CEREBELLUM. 



PREPAKATION. The same methods are applicable as those detailed for the spinal cord. 

 Harden pieces three-quarters of an inch square of a human cerebellum in the Miiller's 

 fluid and spirit mixture (p. xxxii), and proceed just as for the spinal cord. If a human 

 cerebellum cannot be obtained, use that of a cat, dog, or rabbit. Make sections across the 

 folia or leaflets. Stain some with logwood, but preferably with aniline blue-black, and mount 

 them in dammar. 



Vertical Section of the Cerebellum. EXAMINATION (L). Observe the folia or leaflets, with 

 secondary leaflets on them. Notice the dark-stained grey matter outside, and the lighter 

 white matter inside. The grey matter is covered with pia mater, which sends processes 

 carrying blood-vessels into the substance of the organ. It consists of (i) a broad, outer grey 

 or molecular layer, containing at its inner part a single row of pear or flask-shaped cells ; (2) 

 the cells of Purkinje, which give off a number of branching processes, running outward ; 

 inside this is (3) the inner granular or nuclear layer, about one-third the breadth of (i). 

 Observe the large number of small deeply stained granules, arranged in many rows ; and then 

 follows the white matter, consisting of nerve-fibres arranged more or less parallel to each other. 

 (Indicate the layers in PI. XXIV., Fig. i.) 



(H). (i) The outer or cortical layer contains, as a ground-work, a network of delicate 

 nerve-fibrils, and mixed with these are the dichotomously divided branches of Purkinje's cells. 

 It contains a few multipolar ganglion-cells (Sankey), which seem to be connected with these 

 processes. 



(2) Purkinje's cells occur in a single layer. They are of a pear or flask-like shape. Each 

 cell has a single, unbranched, or axial cylinder process, which passes centrally ; whilst from 

 its outer surface it gives off a branched process, which splits up rapidly into branches or pro- 

 cesses which divide again and again. They can be traced nearly to the surface of the organ. 



(3). The nuclear layer is a broad layer, and contains a great number of deeply-stained 

 spherical nuclei, whose exact nature is unknown. Between them is a network of minute 

 fibrils, which are probably nervous in their nature. (Indicate these layers in PL XXIV., 

 Fig. 2.) 



In the white matter note the small nerve-tubes, and between them the neurogleia, con- 

 taining rows of small nucleated cells. 



Trace a blood-vessel in the grey matter, and observe that each one is surrounded by a 

 narrow space the perivascular lymph-space (His). 



DOUBLE-STAINING OF THE CEREBELLUM. 



(1) Eosin and Logwood. Stain a section in a very dilute watery solution of eosin (p. xlv) 

 till it has a faint red colour. This it does in a few seconds. Great care must be taken not 

 to overstain the preparation. This forms an excellent ground-colour. Wash the section in 

 water, and then stain it with logwood, and mount it in dammar. The cortical layer is reddish, 

 and so are the cells of Purkinje, while the nuclear layer, and all other nuclei, have a logwood 

 tint. 



(2) Picrocarmine and Iodine-green. Stain a section with picrocarmine. Wash it in water 



