George L. Streeter 33 



majority of sections there are not more than 5 such cells present. The 

 myelinated axis-cylinders have mostly a longitudinal course, and are 

 about the same size as those in the neighboring periphery of the cord. 

 Throughout the greater part of the nucleus they are uniform in num- 

 ber, 112 were counted in one section, but such a count is subject to 

 error as it is often difficult to say whether the fibres belong to the lateral 

 funiculus or to the nucleus owing to the indistinct inner border of the 

 latter. In studying a complete series of transverse sections through the 

 nucleus, prepared after Weigert's myelin-sheath method, one gets the 

 impression that these large axis-cylinders belong properly to the lateral 

 funiculus. In such sections near its caudal and cephalic ends the 

 nucleus appears as a small island of increased glia tissue lying in the 

 midst of the axis-cylinders near the border of the cord. In the suc- 

 ceeding sections this glia tissue rapidly increases in amount and envelops 

 and carries with it the surrounding nerve-fibres, until finally it bulges 

 from the side of the cord as an exuberant overgrowth. The large size 

 of the nerve-fibres compared to the cells of the nucleus, and their uni- 

 formity in number at difl'erent levels, would also lend support to the 

 view that they are independent of the cells and not properly a part of 

 the nucleus. There are, however, a certain number of fine axis-cylin- 

 ders seen in the sections, both with longitudinal and oblique course, 

 which may be related to the cells embedded in the nucleus. 



The nuclei marginnles minores (Hofmann'sche Kleinkerne) are seen 

 in sections taken from the cervical region at levels where the nerve 

 roots make their exit from the dural sheath and vertebral canal. Their 

 size and general position are indicated in Fig. 1. They do not project 

 from the periphery of the cord and have no appearance of activity. The 

 cells are small and are not definitely multipolar. The glia in which 

 they lie is only slightly increased over that present in other regions of 

 the periphery of the cord. 



The scattered group includes multipolar cells similar to those of 

 the ventral horn, both in shape and size. One or two of these are found 

 in nearly all sections of the lumbo-sacral enlargement, lying among the 

 fibres of the periphery of the ventro-lateral funiculi. They are found 

 most often near the nuclei marginales majores, or among the fibres 

 leaving the cord as the ventral root. It is this group that Kolliker 

 regards as detached elements from the ventral boras. 



In regard to Kolliker s^^ suggestion of a relation between the Hof- 

 inann'sche Grosskerne and the enormous size of the commissura ven- 



1'^ Kolliker, L. c. (c), p. 176. 



