SYMPATHETIC NERVE. 



that the increase in point of thickness of the 

 nerves leaving a ganglion over those which 

 pass to it is due, not to the presence of a 

 greater number of the fibres of Remak, as 

 might be expected were these true nerve- 

 fibres arising from the ganglionic corpuscles, 

 but to an increased number of fine tubular 

 fibres. 



Kolliker * likewise agrees with the authors 

 already mentioned in the view that the fibres of 

 Remak are not to be regarded as true nerve- 

 fibres, but rather as enveloping structures or 

 sheaths to the tubular fibres. He believes, 

 with Valentin, that they are not connected 

 with the ganglionic corpuscle itself, but with 

 its sheath, and are thence continued along 

 such of the tubular fibres as arise from the 

 corpuscles, forming for them a protecting enve- 

 lope or sheath. The capsules of the ganglionic 

 corpuscles are, according to Kolliker, a species 

 of fibrous tissue; and so also the fibres of 

 Remak, which are continuous with them, must 

 be regarded as partaking of the same nature. 

 Again, whilst, on the one hand, these fibres 

 are very abundant in the neighbourhood of 

 the ganglia, in the finer branches, on the other 

 hand, they are much fewer in number, and in 

 the ultimate distribution of the nerve do not 

 exist at all. Similar structures have also 

 been observed by him accompanying the very 

 fine branches of some of the spinal nerves ; 

 such, for example, as those going to the skin, 

 while, at the same time, they are not to be 

 found in the main or larger branches of the 

 same. 



The chief grounds, then, on which it is 

 held that the fibres of Remak are to be re- 

 garded as enveloping structures, and not as 

 true nerve-fibres, are, 1. the anatomical dif- 

 ferences between these and the true or tu- 

 bular nerve fibre ; 2. their resemblance to 

 certain varieties of white fibrous tissue ; 3. 

 their connection with the sheaths of the 

 ganglionic corpuscles, and not with these 

 bodies themselves ; 4. their absence in the 

 final distribution of the nerve ; 5. the in- 

 crease in the thickness of the nerves leaving 

 a ganglion being due, not to an increased 

 number of fibres of Remak, but of fine tubular 

 fibres. 



On the other hand, it has been stated that 

 the anatomical difference between the tubular 

 fibres and the fibres of Remak is not a suf- 

 ficient ground for believing that the latter are 

 destitute of the properties of nerve-fibres. 

 All the nerve-tubes in the embryo, even after 

 it is considerably advanced in development, 

 present much the same character as these 

 fibres, and even after birth nuclei may be 

 occasionally found existing in them. Again, 

 as noticed by Todd and Bowman, the nerve- 

 fibres in the olfactory nerve resemble the 

 fibres of Remak in containing nuclei, and also 

 in the want of double contour, as well as in 

 their soft homogeneous appearance. When a 

 nerve is divided, and a portion of it removed, 



* Mikroskopische Anatomic oder Gewebelehre 

 ties Menschen, von A. Kolliker ; Leipzig, 1850 ; 

 zweiter bind, p. 530. 



the structure by which its continuity is re- 

 stored presents much the same appearance as 

 the fibres of Remak, and this for some time 

 after the part supplied by the nerves has, to a 

 certain extent, regained its functions, showing 

 that impressions may travel along structures 

 not differing from the fibres in question. In 

 reply to the second objection, it is stated that 

 the difference between the fibres of Remak 

 and white fibrous tissue is such as to preclude 

 the notion of the one being a mere variety of 

 the other. In the third place, it is said that it 

 is by no means determined that the fibres of 

 Remak are connected merely with the capsules 

 of the ganglionic corpuscle, and, supposing 

 they were so, that these also may be possessed 

 of the properties of nerve-tissue. 



As regards the relation between the gan- 

 glionic corpuscles and the fibres of Remak, 

 the tubular nerve-fibres which leave the 

 ganglia may not unfrequently be observed to 

 have structures running along each side, which 

 present the same characters as the fibres of 

 Remak ; sometimes only a single row, at other 

 times a double row, of nuclei are placed along 

 each side of the tubular fibre, indicating one 

 or two fibres of Remak. These, on being 



A. Ganglion corpuscles from one of the spinal 

 ganglia in the Mouse, a, corpuscle continuous with 

 a nerve-tube, b. (Mag. 250 diam.) 



B. Ditto from the Gasserian ganglon of the Cat. 

 0, capsule of corpuscle and nerve-tube ; b, cell- 

 mem brane of ganglion-corpuscle. 



c. Cell freed from capsule. 



traced inwards to the ganglionic corpuscle, 

 are found to be distinctly continuous with the 

 capsules of these bodies. When the ganglionic 

 corpuscles are seen separately from one 

 another it is found that these structures are 

 connected only with such of the corpuscles as 

 are still included in their capsules, those 

 which are isolated from their capsules never 

 having any such attached to them (see A, B, 

 and c. fig. 284.) In their general aspect, as well 

 as in their relation towards reagents, the fibres 

 of Remak correspond with the capsules of the 

 corpuscles ; moreover Kolliker has seen and 

 distinctly figures the capsules of these bodies 

 as directly continuous with the fibres of Remak. 

 As regards their dissimilarity to white fibrous 

 tissue, there can be little doubt that when 



