GANGLION-CELLS. 



137 



nerves ; but they are generally reckoned as belonging to the sympathetic 

 system. 



Th? ganglia differ widely from each other in figm-e and size : those 

 ^which have been longest known to anatomists are most of them large 

 and conspicuous objects ; but by the researches of Remak and others, 

 it has been shown that there are numerous small, or what might be 

 almost termed microscopic ganglia, disposed along the branches of 

 nerves distributed to the tongue, the heart, the blood-vessels, the lungs, 

 and some other viscera ; also connected with fine plexuses of nerves 

 between the coats of the intestines. 



Ganglia are invested externally with a thin, but firm and closely 

 adherent envelope, continuous with the fibrous sheath of the nerves, 

 and composed of connective tissue : this outward covering sends pro- 

 cesses inwards through the interior mass, dividing it, as it were into 

 lobules, and supporting the numerous fine vessels which pervade it. A 

 section carried through a gan- 

 glion, in the direction of the 

 nervous cords connected with 

 it, discloses to the naked 

 eye merely a collection of 

 reddish-grey matter traversed 

 by the white fibres of the 

 nerves. The nervous cords 

 on entering lay aside their 

 investing sheath and spread 

 out into smaller bundles, 

 between which the grey gan- 

 glionic substance is inter- 

 posed ; and their fibres are 

 gathered up again into cords, 

 furnished with sheaths, on 

 issuing from the ganglion. 

 The microscope shows that 

 this grey substance consists 

 of nerve-cells and fibres with 

 supporting connective tissue. 

 The nerve-cells have mostly 

 a round, oval, or pyriform 

 figure. They are enclosed 

 in capsules formed of a trans- 

 parent membrane Avith nuclei 

 (fig. 93, h, 94, 95) : these cap- 

 sules are apparently continu- 

 ous with the primitive sheaths of the nerves (M. Sehultze), 



Of the relation between the nerve-fibres in a ganglion and the 

 ganglion-cells, it may be stated that many fibres pass through without 

 ijeing connected with the cells, but that every nerve-cell is connected 

 with a fibre or with fibres. According to Beale, each cell is connected 

 with, at least, two fibres, which, on reaching the nervous bundle in 

 which they are distributed, run in opposite directions (fig. 94). One 

 of the fibres is straight, usually of tolerable size, and connected with 

 the cell at one spot like a stalk — in pyriform cells at the small end. 

 The other, usually smaller, begins or is attached at some distance 



FROM 



Mag- 



Fig. 93. — Multi-Polar Ganglion Cells 

 Sympathetic of Man (Max Sehultze). 

 nified. 



a, fi-eed from capsule ; b, enclosed within cap- 

 sule. The processes of both are broken off a short 

 distance from the cell. 



