955 



provided with an oil immersion (Vi, a) and ocular four. The 

 preparations were investigated in the most careful way step by step, 

 but not a single example of a division of the nerve fibres could be 

 discovered, either in the roots or in the continuation of the nerve 

 fibres in the ventral horn through the spinal cord up to their root 

 cells. 1 observed a few cases of spinal ganglion-cells which had the 

 claviform processes mentioned above. These claviform formations 

 were, however, always within the capsules. In no case, however, 

 was I able to discover anything that could be interpreted as a 

 division within the spinal ganglion of either the central axon or 

 that which passes peripherally. I tried to test the negative results 

 obtained from this investigation in another way, in order to obtain 

 if possible a positive result. I made cross-sections of the silver 

 impregnated material through the corresponding nerve roots on the 



Fig. 1. Schematic representation of the neural growth in the 

 dorsal and ventral roots of the spinal nerves, (a) Cross section at 

 the place with the smaller and {b) cross section at the place with the 

 larger number of nerve fibres in the dorsal root, («i) Gross section 

 at the place with the larger and (öj) cross section at the place with 

 the smaller number of nerve fibres in the ventral root at a spinal 

 nerve from a young animal, (c) Gross section peripherally of the 

 spinal ganglion, (d) Spinal ganglion cell, (e) Ventral root cell. 



other side, some close to the spinal cord {a and ^i ; fig. 1) and 

 others close to, but centrally of, the spinal ganglion (6 and 6, ; fig. 1). 

 As the nerve roots that f investigated belonged to the lumbal and 

 sacral nerves, which take part in forming the quada equina, the 

 distance between the two cross sections was fairly great. The nerve 

 fibres in the sectioned preparation were counted. There are three 

 possibilities for the totals that we might expect to obtain for the 

 numbers of nerve fibres. If we take a; a^; b and /), fig. 1 to denote 

 the number of nerve fibres, then a =r b or else ay> b or finally 

 a <^b. \ï a = b then one could scarcely expect any appearance of 

 axon-division or any figures of growth in the piece ab; if, on the 



