ORGANS OF THE BODY. 



593 



as incorrect. The process mentioned remains undivided (d), and, becom- 

 ing clothed with a layer of medullary substance (e), may be regarded as 

 the ordinary axis-cylinder process of the central ganglion cells (Deiters, 

 Koscliewnikoff, Hadlich, Boll). 



Externally that is, directed towards the surface of the cerebellum 

 these large ganglion cells send off 

 several (generally two) character- 

 istic protoplasm processes through 

 the so-called "molecular layer of 

 Hess" These then gi^e origin to 

 regular systems of branches, thin 

 at first, and running down to the 

 most delicate terminal filaments 

 finally (c, c, /, /). Taken as a 

 whole, they present somewhat the 

 appearance of a stag's antlers. Com- 

 misstiral union of one cell with 

 another, by means of these pro- 

 cesses, does not occur. On the 

 contrary, the discovery of Hadlich 

 (if it be confirmed) is of great 

 interest (fig. 561), namely, that 

 these finest filaments of the arbo- 

 rescent system of ramifications (a) 

 bend over on arriving near the 

 surface of the cortex in shorter or 

 longer arches, and run inwards 

 again through the grey layer in the 

 direction of the granular layer of the 

 rust -brown stratum. Before they 

 reach this, however, they sink into 

 a very delicate filamentous network, 

 according to Boll, which is spread 



Fig. 561. Section through the cortex of the 

 human cerebellum (after Hadlich). Two gan- 

 glion cells of Purkinje; below them a part of 

 the granular layer. At r, sustentacular fibres; 

 a, the looped filaments of the delicate ramifica- 

 tions of the ganglion cells; c, finest tangential 

 nerve fibres. 



through the whole of the grey 

 matter. This network would cor- 

 respond, then, to that described by 

 Gerlach in the interior of the spinal cord. From it then, in the granular 

 layer stronger nerve-fibres are said to arise. 



The nerve fibres of the white internal portion of the cerebellar convo- 

 lutions pass outwards to the grey covering layer, interlacing at the same 

 time. They pass into the rust-brown layer, radiating like hairs of a paint- 

 brush. Here most observers state (we believe correctly) that they undergo 

 extensive subdivision, so that only very fine twigs reach the under surface 

 of the large, remarkably formed ganglion cells. They appear at last to 

 terminate in the fine neural network of Gerlach. The axis-cylinder 

 processes, on the other hand, of these strange ganglion corpuscles pass 

 inwards towards the white substance. 



The nervous plexus of the rust-brown layer is continuous, with rapid 

 diminution in the thickness of its fibres through the internal third of the 

 molecular layer. 



The framework of the grey layers is formed of ordinary spongy susten- 

 tacular tissue (Koellilcer, Rutkotpsky), with those scattered nuclear elements 

 of which, according to Schulze, two kinds may be distinguished. 



