WORK UPON VISCERAL AND ALLIED NERVES. 75 



in the central grey matter, terminates dendritically at the 

 position of the second nerve cell. The second cell is 

 found situated in various positions, either in the lateral 

 chain of ganglia, i.e., those having a white ramus running 

 to them, or in the collateral ganglia such as the superior 

 cervical ganglion, or the mesenteric ganglia, or finally, in 

 peripheral ganglia placed in or very near the organs them- 

 selves, e.£-., in the heart, the internal generative organs, 

 etc. In his latest paper, Langley ^ gives, as the conclusion 

 he has drawn from his many experiments, that "each vis- 

 ceral nerve fibre has one nerve cell on its course and one 

 only. More accurately, that a visceral nerve impulse on its 

 way from the central nervous system to the periphery 

 traverses one nerve cell and one only." He considers that 

 each fibre which leaves the central nervous system divides, 

 and that each division is connected with a nerve cell. As 

 a rule all the divisions terminate in the same ganglion, but 

 in some cases there is evidence to show that one or more 

 of the collateral divisions may terminate in a second gcmg- 

 lion, or along a nerve strand, proximally or distally to the 

 termination of the major number of the divisions. Further, 

 that where there are several prse-ganglionic fibres running to 

 the same or to analogous parts, they nearly all terminate in 

 the same ganglion, though here again exceptions may occur, 

 some few fibres terminating with a slightly shorter or longer 

 course. 



In many cases the post-ganglionic fibre is non-medullated, 

 but this is by no means a general rule, for Langley ^ has 

 shown that many finely medullated fibres occur in grey 

 rami and elsewhere which are neurons from cells in the 

 various ganglia. 



A point of considerable interest is with regard to the 

 part played by the nerve cell which is interpolated upon 

 the course of the fibres uniting the viscera to the centre. 

 Reflexes may be obtained from some of these ganglia, but 

 Langley and Anderson have shown that these reflexes are 



^ Journ. of Physiol, vol. xx., p. 223, 1896. 

 -Ibid., p. 55, 1896. 



