88 TISSUES OF THE NERVOUS SYSTEM. 



whether the spiral fibre is connected with these nuclei, as has 

 been supposed, by a network of extremely fine filaments from 

 which it appears to spring, cannot be determined any more 

 certainly than the question whether, in multipolar cells in gene- 

 ral, the processes spring entirely from the substance of the cell, 

 or one or other of them from the nucleus. 



Reproduction of Ganglion Cells. The ganglion cells of 

 the sympathetic system seem to undergo very active develop- 

 ment. This appears, first, from the frequency with which cells 

 containing two nuclei are met with; secondly, from the cir- 

 cumstance that frequently two, three, or four polyhedral cells 

 occur in a common capsule; thirdly, from the occasional oc- 

 currence of two club-shaped cells in one capsule, so placed that 

 they are in apposition by their flat bases, while their sharp 

 ends are continuous with processes ; and finally, that in many 

 organs, as, e. <?., in the (male) genital tract, and in Meissner's 

 ganglia of the newly-born foetus; groups (so-called " nests") of 

 extraordinarily small ganglion cells occur. If the Auerbach's 

 ganglia of the rabbit's intestine are prepared as directed above, 

 and covered in serum, they are found to consist of a network 

 of bands of various breadth, the nodes of which constitute 

 broad plates of irregular form, the whole being invested by a 

 sheathing in which nucleus-like structures are distinguishable. 

 The substance both of the nodes and of the bands which connect 

 them is finely streaked or granular. A greater or less number 

 of ganglion cells mostly globular inform, are embedded in this 

 substance, and arranged either in groups (in the nodes) or in 

 rows (in the bands). In the latter, the chains of cells are inter- 

 rupted at intervals; the former exhibit numerous perforations, 

 which are merely the interstices of a dense meshwork of bands. 

 In gold preparations, these facts can also be easily demon- 

 strated. 



In preparations made in the same manner from the intestine 

 of a nearly mature human embryo, it is possible to make out 

 that, in the reticular system above described, numerous small 

 cellular structures occur, embedded in the substance both of 

 the bands and nodes, in most of which all that can be seen is a 

 nucleus surrounded by a very narrow entourage of granular 

 substance: a few present the ordinary characters of ganglion 

 cells. 



In sections of intestine of the rabbit hardened in chromic 

 acid (as we shall see in Part II.), the connection of these gan- 

 glia with the ganglionic masses of similar form which exist in the 

 circular fibres, and communicate towards the mucosa with the 

 ganglia of Meissner, can be well seen. 



