XXXIV] THE CEREBRUM AND CEREBELLUM 2T3 



speaking its cells diminish in size from within outwards. 

 Small angular cells may be seen in its deepest part. 



e. Outside the preceding layer is a thin layer with 

 numerous small pyramidal cells, the peripheral process 

 being usually distinct ; this is the 2nd layer. 



The 1st layer of the cortex, consisting of a fine 

 network of fibrils showing a few very small cells. 



Blood vessels may be made out in all portions of 

 the cortex ; they are usually most conspicuous in the 

 outer layers of the cortex, running into it from the pia 

 mater. 



2. Section of cortex of cat or dog (chrome-alum 

 mixture ; medulla stain). Note the radiating bundles 

 of fibres from the white substance into the grey. 



3. Section of a lobule of the cerebellum extending 

 from the surface to the inner white substance and at 

 right angles to the direction of the folds. Observe 



The inner strand of medullated nerve fibres spread- 

 ing into 



The nuclear layer, formed mainly of small cells 

 closely packed together ; these cells have a very small 

 amount of cell substance, so that probably their deeply 

 stained nuclei only will be seen. 



A single layer of large, somewhat globular cells 

 (Purkinje's cells); each has a large peripheral process 

 which will be seen to branch, and the branches to 

 branch again and so on, eventually extending as fine 

 branching fibrils nearly to the surface of the cortex; 

 close to the surface the fibrils become lost to view. 

 Since the branches, especially the larger ones, run to 

 some extent laterally, the processes from neighbouring 



L. 18 



