SYMPATHETIC NERVE. 



439 



mcnt in the ganglion, it is difficult to deter- 

 mine. Kolliker* has observed that the nerve- 

 tube arising from a ganglionic corpuscle fre- 

 quently makes one or two turns around it 

 before pursuing its course towards the peri- 

 phery ; arid it appears probable therefore that 

 many of the so-called umspinnende fasern may 

 be of this description. That the nerve-fibres 

 connected with the ganglia do not merely pass 

 through it between the ganglionic corpuscles, 

 as was formerly supposed, but enter into 

 intimate organic connection with these bodies, 

 either arising from them, or having these 

 bodies developed upon them in their course 

 from the centre towards the periphery, as 

 seems to be the case with most of the bipolar 

 cells, is quite certain. 



Aves. In the bird the ganglia present 

 much the same structure, both as regards the 

 ganglionic corpuscles and nerve-fibres, as 

 those of the mammalia. 



Reptilin. In the frog, the animal in this 

 class which has been most frequently ex- 

 amined, the ganglionic corpuscles present the 

 same general characters as those in the higher 

 animals. The existence of apolar and uni- 

 polar ganglionic corpuscles is much better seen 

 in examining the small ganglia in the heart or 

 bladder of this animal than in the ganglia of 

 the mammal or bird. Bipolar cells have been 

 described by Schiff; Valentin f has also de- 

 scribed and figured bipolar ganglionic cor- 

 puscles the nerve-tubes of which ran in 

 opposite directions, one towards the centre, 

 the other towards the periphery. They were 

 found by him both in the small ganglia of the 

 heart, and also in the ganglia occurring in the 

 main chain of the sympathetic. The nerve- 

 tube connected with these he describes as 

 clear and transparent, differing from the broad 

 nerve-fibres in its colour and general appear- 

 ance, especially in its not presenting any oily 

 contents, and thus appearing to belong to 

 the fine variety of fibres. Kolliker describes 

 the unipolar ganglionic corpuscles as being 

 pyriform, and at their narrow extremity drawn 

 out into a delicate process. This presents 

 the same pale and finely-granular appearance 

 as the corpuscle itself, and measures from the 

 Y^ijr^th to the j-J^g-th of an inch in dia- 

 meter : after running a short distance from the 

 ganglionic corpuscle it acquires a dark margin 

 and slightly granular contents ; becoming, in 

 short, a fine nerve-fibre (see fig. 289. A). 

 Bidder has also observed in the ganglia of 

 the heart of the frog bipolar cells, which, 

 however, resembled the unipolar in the fact 

 that both nerve-tubes ran in the direction of 

 the periphery. In the ganglia of the frog there 

 is a much smaller amount of the substance 

 present, which has been described as consti- 

 tuting the capsules of the ganglionic corpuscle, 

 and there are also very few of the fibres of 

 Remak. 



Pisces. In certain animals belonging to 

 this class, especially in the cartilaginous fishes^ 



* Mikrcskopische Anatomic. 

 f Valentin, Lehrbuch der Physiologic, 

 scliweig, 1848 ; band ii. p. 602. et seq. 



the 'connection between the ganglionic cor- 

 puscles and the nerve-tubes is much better 

 seen than in any of the preceding classes. 

 In the torpedo and ray the bipolar variety of 

 ganglionic corpuscles was first discovered by 

 Wagner, and shortly afterwards by Robin. 

 Similar observations were also made by Bid- 

 der and Reichert, both as regards the car- 

 tilaginous fishes, and, by the latter observer, 

 in the cod, perch, and certain species of sal- 

 mon, as well as in the pike.* In the common 

 ray the ganglionic corpuscles, as occurring in 

 the spinal ganglia, are generally more or less 

 round or oval, and are much larger than in 

 any of the higher animals. They measure 

 from ^i^th to the ir ^ 7 th of an inch in dia- 

 meter, and contain a more or less clear viscid 

 fluid with finely molecular matter. On the 

 addition of diluted acids or spirit, they be- 

 come dark and granular. Each of the cells 

 contains a clear round nucleus, in which there 

 is also present one, sometimes two, nucleoli. 

 The contents of the nucleus, like those of the 

 cell itself, become dark and granular on add- 

 ing the reagents above mentioned. In se- 

 veral of the cells there are seen, apparently 

 on the inner surface of their wall, a num- 

 ber of round corpuscles, generally clear and 

 transparent, but sometimes more or less 

 dark and granular. They measure about the 

 __i_-th of an inch in diameter, and seem, as 

 Wagner and Robin describe, to form a single 

 layer on the inner surface of the ganglionic 

 corpuscles. The larger of the ganglionic 

 corpuscles are generally more or less spheri- 

 cal ; the smaller, on the other hand, present 

 commonly a more oval shape. Sometimes 

 between the outer cell-wall and the contents 

 of the vesicles there is, as Bidder describes, 

 a clear space, varying in breadth, generally 

 broadest at the points where the two nerve- 

 tubes are connected with the corpuscle ; at 

 other times this space does not appear to 

 exist, the granular contents of the vesicle 

 coming close up to the cell-wall (see A. 

 and v.Jig. 286.). The wall of the corpuscle 

 appears to be much stronger than that of 

 those in the higher animals, and is distinctly 

 prolonged at either extremity into the mem- 

 brane of the nerve-tube, the two constituting 

 one continuous structure, agreeing both in 

 anatomical characters and in their relation 

 towards reagents. When the ganglion-ve- 

 sicle is ruptured, so as to allow its con- 

 tents to escape, its cell-wall collapses more or 

 less, and often presents the appearance of 

 lines passing outwards towards the circum- 

 ference, from a central point (H. Jig, 286.) 

 this appearance is evidently due to folds in 

 the membrane. In the clear space which has 

 been mentioned as sometimes existing be- 

 tween the cell-wall and the contents of the 

 ganglionic corpuscle, there are often observed 

 a number of particles, most abundant at the 

 two poles of the vesicle, which resemble in 

 appearance the curd- like contents of the nerve- 



* Canslatt's Jahresbericht, 1847, also Wagner's 

 Braun- Handworterbuch der Physiologic, baud iii. p. 361. 

 et seq. 



F F 4 



