OF DENISON UNIVERSITY .7 



able that the groups of ganglion cells, from which the cranial nerves 

 arise, and which have been made known by StilHng as the nuclei of 

 sensory roots, consist of cells in form entirely similar to those from the 

 anterior and posterior cornua of the si)inal marrow, and that they, hke 

 these, send off only one axis cylinder, which passes toward the per- 

 piphery, while the other processes divide into innumerable primitive 

 fibrils.'"* 



Turning to the morphological aspects of the same problem, the 

 results are similar. Thus in the literature before 1870, although all 

 agreed that the cortex is laminated,- Baillarger (1840), Gerlach (1852), 

 Berlin (1859), and others, described six layers, Koelliker, four to six, 

 Arndt, five to six, and Meynert, nine. The giant pyramids or 

 "pyramidal bodies," (Meynert), were described by Arndt as pyra- 

 mids with five or more fine branches from the base, which divide 

 dichotomously and are lost in a nervous reticulum of the ground 

 substance, while the apex process passes upward, then abrujitly turns 

 downward to form an axis cylinder. Meynert, and after him Loech- 

 ner, Kollman and Stieda, on the contrary, claim that the apical pro- 

 cess divides, while, besides the baso-lateral processes there is a me- 

 dian basal double-contoured fibre which passes into an axis cvlinder. 



Meynert say, (Psychiatry, p. 70): "Betz has stated that the ante- 

 rior central convolution contained groups of particularly large |)yra- 

 mids, which he thought were the circumscribed motor centres which 

 Hitzig, on the strength of his physiological experiments, relegated ex- 

 clusively to the anterior central convolution of the brain of dogs and 

 monkeys. Apart from the mistake which Hitzig made in establishing 

 the homologue in carnivora of the anterior central convolution, it has 

 been proved that the size of the pyramids depends upon their distance 

 from the cortical surface. The largest pyramids will, therefore, be 

 found in the broadest cortical region ; but the broadest cortical region 

 is that of both central convolutions. '-^ * * The largest i)yramids 

 appear to be arranged in small groups at some distance from one an- 

 other. It would be wrong to argue from this that these large pyramids 

 have a different signification from the smaller ones. Luys is in a great 

 measure responsible for this mistake. Betz aj)pears to me not to have 



[* /^aue, Psychology as a Natural Science applied to the Solution of Occult 

 Psychic Phenomena, 1S89.] 



