184 



shown that sharp and characteristic differences exist between the neu- 

 rones of the visceral sensory column (1. vagi) and those of the so- 

 matic sensory column (nucleus funiculi and acusticum). "In the cord 

 in the region of the first and second spinal nerves a few cells situated 

 in that part of the gray matter which represents the dorsal horns 

 send dendrites into both the deeply staining and pale tracts. Other 

 cells, situated nearer the median line, dorsal to the central canal, send 

 dendrites into the pale tracts alone. Farther forward the latter cells 

 become sharply distinguished in form and size from the cells of the 

 nucleus funiculi, which no longer send dendrites into this median dorsal 

 region. The great majority of these cells, which constitute the vagus 

 lobe, are situated close to the central cavity. Some of them are com- 

 pact but with very rough or irregular bodies, while others are greatly 

 elongated. Behind the commissura infima Halleri some cells lie in or 

 near the middle line and send their dendrites to both sides. These 

 are to be regarded as belonging to the median nucleus of Cajal. The 

 dendrites are relatively short, thick, very profusely branched, and the 

 final branches are very slender sinuous twigs. The great difference 

 of form between the cells of the lobus vagi and those of the nucleus 

 funiculi is shown in Fig. 21. The neuntes are traced laterally and 

 ventrally into the lateral tracts. The fibers are fine and in most parts 

 of the lobe are not sufficiently numerous to form a bundle, so that it 

 has been impossible to trace them to their destination. They do not 

 bend in the direction of the arcuate fibers" (1902, p. 23 — 24). I pre- 

 sent here figures of a few cells to illustrate further the differences be- 

 tween the two sensory gray columns. In Fig. 1 is shown a single 

 large neurone of the nucleus commissuralis whose cell body stretches 

 across the middle line. The interlacing of the branches of the dendrites 

 toward the right is more dense and complex than is shown in the 

 figure. From the end of the cell on the right side the axone arises 

 as a slender fiber which increases in diameter and is traced through 

 the right dorsal group of Müllerian fibers to the ventro-lateral region 

 where it seems to turn to become a longitudinal fiber. 



In Fig. 2 are shown two neurones taken from the cephalic part of 

 the nucleus commissuralis. The cell body of the neurone to the right 

 was incompletely impregnated. In the case of each of these neurones 

 the axone arises from a dendrite at some distance from the cell-body. 

 The axone is slender, direct in its course, slightly varicose and is as 

 clearly characterized as are the axones of cells in the higher animals. 

 The axones take a ventro-lateral direction but soon pass out of the 

 section. In Fig. 3 is drawn another cell from the nucleus commis- 



