56 GRAY SUBSTANCE OF THE TRAPEZIUM, 



Some of the fibres from the anterior division of the auditory enter the cells lying 

 in the immediate vicinity of the apex, the processes from these cells serving to 

 connect the roots with the caput cornu, w^hich is also brought into very intimate rela- 

 tion with this portion of the nucleus by means of wavy bundles of fibres, some of 

 which are apparently continuous with the roots (Plate XVI, Fig. 44). Schroder van 

 der Kolk, who considers the caput cornu as the trunk of the great trifacial nerve, 

 thinks that a connection is established between this nerve and the auditory by means 

 of these fibres radiating from the nucleus of the latter, but this conclusion is I think 

 incorrect. The caput cornu, as has been shown by Clarke, and fidly confirmed by 

 my own observations, contains in its substance numerous longitudinal bundles which 

 are descending roots from the trifacial, but is certainly mainly composed of quite 

 distinct cell groups constantly increasing in number as we ascend. I have not 

 been able to trace a direct communication between any of these longitudinal bun- 

 dles and the fibres radiating from the auditory nucleus, and the latter more probably 

 enter the cells of the caput, which are especially numerous near the upper part of 

 the auditory tract. The nuclei of all the nerves of the •posterior column^ spinal accessory, 

 vagus, glossopharyngeal and auditory appear to be connected with the caput cornu, 

 which finally becomes itself a part of the nucleus of the trifacial, and may possibly 

 serve to a certain extent throughout the medidla, to co-ordinate and bring into 

 harmony all these different nerves. Another set of fibres from the anterior 

 division of the auditory enter more deeply into the nucleus, and bend forwards 

 into the antero-lateral network, either with or without passing through cells. 

 Many of these fibres join the numerous bundles coming down from the cerebellum, 

 and pursue the same course, radiating into the antero-lateral network ; they cross 

 the facial roots, and occasionally join their course for a short distance, but I have 

 been able to satisfy myself that no direct connection is established. 



Schroder van der Kollc states that many slender fibres pass from the nucleus 

 of the auditory towards the facial nucleus, " so that no doubt can exist of a connec- 

 tion between these nuclei."^ Though I have carefully examined many specimens 

 in which the course of the fibres could be studied with great certainty, and have 

 often been able to trace fibres from the auditory nucleus across or even into the 

 substance of the facial nucleus, I have never been able to trace them with certainty 

 into the cells of the latter, and although a connection to some extent is quite probable, 

 I have been unable to see any sufficient grounds for so elaborate a theory of the 

 reflex action of the auditory on the facial as is attempted to be established by 

 Schroder van der Kolk {I. c). Many of the fibres from the anterior border 

 of the auditory nucleus may be traced across or behind the fasciculus teres to the 

 raphe, where they are either seen crossing directly to the other side, or sometimes 

 passing along the raphe for a short distance before crossing. Some of these fibres 

 are undoubtedly either direct continuations of the anterior and posterior divisions 

 of the root, or fibres derived from the cells entered by these, while others seem to 

 be bundles coming directly from the cerebellum. At any rate by means of these 

 bundles which are very numerous, and in many preparations very easily traced, the 



' Medulla Oblonsata, 116, lit. 



