The radix mesencephalica trigemini.

The first author to correctly describe the midbrain or "descending" root of the trigeminus was Meynert.I n his chapter on the brain of mammals contributed to Stricker's Handbuch der Lehre von den Geweben, he describes the root in the following manner : '"This root descends along the outer side of the central, tubular gray matter of the aqueduct, and passes onward through the region of tho pons, in the meantime constantly increasing in bulk, and buried in the lateral region of the gray floor of the ventricle that lies along the inner surface of the processus cerebelli ad cerebrum.It presents on cross-sections a semi-lunar surface, which Stilling and Deiters took for an ascending trochlearis-root, and along its inner border lie, through a large part of its course, the clusters of cells from which the fibers of the root spring, so disposed as to remind one of grape clusters.These cells are distinguished from those of the substantia ferruginea by the roundness of their form, and by their containing no pigment" (American edition, p. 7 3 3 ) .H e does not discuss the possibility of the root being motor in character, but simply describes it as one of the primary