XXXI.] CEREBELLUM. 351 



Numerous blood-vessels enter the surface of the cerebellum from 

 the pia mater covering it. 



(b.) At the boundary-line between (i.) and (ii.) a row of large 

 cells Purkinje's cells each with a somewhat oval or globular 

 body, with a single central process, which becomes continuous with 

 a nerve-fibre, although this is not seen in this preparation. Each 

 cell gives off a peripheral process, which immediately branches, the 

 larger branches running laterally for a short distance, arid each 

 branch divides again and again, the fine branches protoplasmic 

 processes or dendrites running vertically through the outer layer 

 of the cortex nearly to its free surface. The branched arrangement 

 of these fibres has been compared to the antlers of a stag. 



By means of the rapid Golgi method, a basket-shaped complex 

 of fibrils can be seen round the basis of Purkinje's cells. 



(c.) (H) The granular or nuclear layer, with two kinds of nuclei 

 or rather cells. The most numerous are small and granular, and 

 arranged in groups ; they are stained violet by the haematoxylin. 

 The others (larger and spherical, with a nucleolus) are the nuclei 

 of small ganglionic nerve-cells. They are stained reddish. Amongst 

 the granules may be seen medullated fibres stained reddish. 



The more recent methods of Golgi and Ramon y Cayal show 

 that these two kinds of cells correspond to nerve-cells. The 

 small cells have an axis-cylinder and several protoplasmic pro- 

 cesses, while the large cells in some respects resemble small 

 1'urkinje's cells. 



4. Blood- Vessels of the Cerebellum. These are injected when 

 the blood-vessels of an animal are injected from the aorta with a 

 Berlin-blue or carmine-gelatine mass. Mount an unstained sectin 

 in balsam (L and H). 



(a.) Observe the vascular pia mater sending at intervals long or 

 medullary branches through the cortex to the medulla, and short 

 or cortical branches which break up into a rich plexus of capil- 

 laries in the cortex, so that the latter is far more vascular than the 

 white matter. Each vessel is surrounded by a perivascular lymph- 

 space. 



CEREBRUM. 



Methods. Harden it in the same way as the cord and cerebellum. 

 For Golgi's methods (p. 345). 



If Weigert's method is used, the sections must remain for twenty- 

 four hours in the hamiatoxylin solution in order to see the plexus of 

 medullated fibres in the superficial layers of the cortex, and three, 

 hours for the fibres which ascend between the pyramidal cells of 

 the cortex cerebri. 



5. V.S. Cerebrum. Make V.S. through the central part of the 



