756 



which are undoubtedly endymal or supportive in function and on the 

 ectal boundary, cells which are unquestionably nervous, there exist 

 between these two limits cells representing both functions to a greater 

 or less extent and they may therefore appropriately be denominated 

 neurendymal cells. The fact that the neuntes originate from the 

 dendrites seems to me very strong evidence that the latter are nervous 

 in function. 



In the myel there seems to be a distinct difference of caliber 

 between the fibers of the dorsal and ventral roots, the former being 

 the courser. In their passage from the periphery to the myel the 

 dorsal root fibers assume very complex relations among themselves 

 and with the ventral root fibers in the ganglion. There are three 

 distinct nerve trunks given off from the ganglion ; the first and largest 

 passes off in a ventro- lateral direction and corresponds to the ordinary 

 spinal nerve trunk as found in the majority of vertebrates. The second 

 passes in a latero-caudal and somewhat dorsal direction while the 

 third extends dorsally. The second and third trunks are of about 

 the same size and ventral and dorsal root fibers were found in all 

 three. In the latero-caudal trunk the dorsal root fibers bend upon 

 themselves at quite an acute angle to enter the myel through the 

 dorsal root; and in the dorsal trunk where these fibers would have 

 to bend at a very acute angle to enter the myel through this root, 

 the bending could still be demonstrated. The ventral root divides 

 near the myel and sends fibers to both the latero-caudal and dorsal 

 trunks as well as to the ventral trunk. 



The division of these fibers in the ganglion itself to form nerve 

 trunks is an unusual occurrence, although their division just outside 

 of the ganglion is not infrequent. Schaffer (Vergleichend- anatomische 

 Untersuchungen über Rückenmarksfaserung, Arch. f. mikr. Anat., 

 XXXVIII, p. 157 — 176) notes and figures a ganglionic division of the 

 ventral and dorsal roots in the Anguis fragilis, and that in this 

 crossing of the fibers there result two bundles the larger of which, 

 the ramus communicans v en tralis, contains the motor elements 

 of the dorsal root, the more slender bundle, the ramus communi- 

 cans dorsalis the sensory elements of the ventral root; so that 

 there pass out from the ganglion two nerves. His in 1888 showed 

 that there enter into certain of the cranial nerves, fibers which are 

 not ganglionic in their origin but from their source are evidently 

 efferent or motor in function and in this apparently dorsal root there 

 are found two elements one of which, the efferent, Minot (Structural 

 Plan of the Human Brain, Popular Science Monthly, XLIII) calls the 



