462 SPECIAL HISTOLOGY. 



in the latter case anastomose, simply traverse it, to be re- 

 united below the ganglion into a single trunk, which is then 

 immediately blended with the motor root. Most of the nerve- 

 cells themselves appear to be in connection with nerve-fibres, 

 giving off either one or two, or, more rarely, several. These 

 fibres, which I term ganglion-fibres, proceed in a prepon- 

 derating majority, perhaps all of them peripherally, joining 

 and strengthening the perforating root-fibres; so that each 

 ganglion is to be regarded as a source of new nerve-fibres. 



[The structure of the spinal ganglia (fig. 154) is a difficult 

 subject for investigation, in Man. No complete results can 

 be obtained from the larger of them, but more may be made out 

 in the smaller or smallest, as in those of the fifth sacral nerve 

 and n. coccygeus, which are to be sought within the sac of the 

 dura mater, also perhaps in the fourth sacral and first cervical 

 nerves. If a comparative examination be instituted, of the 

 spinal ganglia of the smaller Mammalia (Rabbit, Puppy, Mole, 

 Mouse, Rat), and if not only the scalpel and needle be em- 

 ployed, but if the entire ganglia be examined after the applica- 

 tion of acetic acid, and above all, of a dilute solution of soda, 

 with the aid of the compressorium, a satisfactory insight into 

 their structure mav be obtained. The fibres of the roots of 

 the nerves while passing through the ganglia present nothing 

 at all peculiar, that is to say, no change in size; nor have 

 I ever observed any divisions of them, and I think it may 

 be positively asserted, that such an occurrence, if it take place 

 at all, must be extremely rare, as, notwithstanding that I have 

 specially sought for it, and have been able, in the lower 

 Mammalia, to trace numerous nerve-fibres through the entire 

 ganglion, I have never noticed anything of the sort. 



The principal constituents of the ganglia — the ganglion- 

 globules or -cells [nerve-cells] (figs. 155 and 157), have a dis- 

 tinct outer coat, are for the most part roundish, elongated, or 

 pyriform, usually a little flattened, and measure from 0012 to 

 : 036"', or even 004"'; on the average 0-02— 003'". The 

 contents are throughout finely granular, and not unfrequently 

 exhibit, in the vicinity of the nucleus, an accumulation of yellow, 

 or yellowish-brown, larger pigment granules, which increases 

 in age, and to which the ganglia are chiefly indebted for their 



