362 Undescribed Nucleus Lateral to the Fasciculus Solitarius 
border of the fasciculus, while others are separated from it by a 
distance varying from 0.2 to 0.7 microns. These nerve cells are appar- 
ently quite distinct from those scattered among the descending root 
bundles of the acusticus, which at this level pass down quite near the 
fasciculus solitarius. The cells of this nucleus are much larger, of 
different shape, and stain more deeply with carmine than the cells 
among the descending root bundles of the acusticus. The cells of 
Deiter’s nucleus first appear in the cross-section of the medulla at a 
Fie. 2. Fasciculus solitarius and nucleus ‘‘y” in the dog. (Drawing made from 
photograph.) F.8., fase. solitarius; X. N., bundles of the outgoing vagus. Four 
cells of nucleus ‘‘y”’ to the right of the fasc. solitarius. 
considerably higher level and are separated from these cells by too 
great a distance for them to be looked upon as an extension downward 
of Deiter’s nucleus. 
In examining sections from three human medullas (in two of which 
the series was complete) I find in all a small, round, compact collection 
of cells, lateral to the fasciculus solitarius, in nearly the same relative 
position as the cells just described in the dog. In man this clump of 
cells is first met at a level somewhat higher than that described above 
