94 



THE ESSENTIALS OF HISTOLOGY. 



separated by the bundles of nerve-fibres which are traversing the 

 ganglion (fig. 108A). The ganglion if large is inclosed by an investing 

 capsule of connective tissue which is continuous with the epi- and peri- 

 neurium of the entering and issuing nerve-trunks. 



Many nerve-cells, and notably those of the spinal cord, have a finely 

 fibrillar structure. The fibrils can be traced into the branches of the 

 cells and into the axis-cylinders of nerve-fibres which are connected 



with the cells (fig. 110). Other- 

 wise the cells have a finely 

 granular appearance ; often with 

 a clump of black, brown, or 

 yellow pigment-granules placed 

 at one side of the nucleus. 



In preparations made by 

 Golgi's nitrate of silver method 

 the nerve-cells and their pro- 

 cesses are coloured black by a 

 deposit of reduced silver, so that 

 the processes can be traced for 

 a considerable distance from the 

 body of the cell, in fact in some 

 instances as far as their remotest 

 ramifications (fig. 112). It is 

 found by the employment of 

 this method that the axis- 

 cylinder process is not always 

 an unbranched process, as was 

 formerly supposed, but that it 

 usually, if not invariably, gives 

 off fine lateral branches (col- 

 laterals), which themselves tend 

 to ramify in the adjacent nerve- 

 substance. And, although the 

 main part of the axis-cylinder 



FlG. 111. MULTIPOLAR NERVE-CELL FROM AN- -.-ntH*** nanalKr nnc f\n anrl 



TERIOR HORN OF SPINAL CORD, HUMAN. Pcess usually passes on and 

 (Gerlach.) becomes part of a long medul- 



, Axis-cylinder or nerve-fibre process; 6, pigment. ^^ nerye . fibre (firgt type of 



Grolgi), this is not always the case, for in another type of nerve-cell 

 within the nerve-centres (second type of Grolgi), the axis-cylinder 

 process breaks up after a short course into a terminal arboresence, 

 which usually envelops other nerve-cells. 



Moreover, even the long process of type 1 (which becomes the axis- 



