168 A STUDY OF THE SUPERIOR OLIVE. 



granular cell, scattered irregularly through the nuclear area and the surrounding 

 parts. The spindle-cells are closely packed, side by side (like small fish in a tin), 

 their extremities pointing toward the periphery of the nuclear fold, the long axis 

 of the cell being placed at right angles to the long axis of the nuclear coil. This 

 condition is especially apparent and regular in the medial mass of the nucleus, as 

 this portion corresponds more nearly to a straight line than does the S-shaped 

 lateral mass, though in the latter the spindles extend crosswise of the fold, thus 

 conforming to type. 



Some of the cells present irregularities in outline, though all are sufficiently 

 close to type to justify one in classifying them as belonging to the same general cell 

 family which is characteristic of this nuclear mass. The different animals exhibit 

 some minor variations. In the adult dog, for example, in proportion to the fiber 

 network, the cells are less numerous than in other animals, and thus the difference 

 between the spindles and the tapering oval cells is more clearly defined. The 

 spindles are quite deeply stained, while the tapering, oval cells are very pale and 

 rather indefinite. In the cat the staining reactions are similar, though the ovoid 

 cells are much more in evidence and take the stain better, and the total cell-content 

 is vastly greater than in the dog. 



In human tissue, aside from a few granular cells, only true spindle-cells are 

 found. These present the characteristic shape, position, and relations as those 

 described for other animals. The cells are deeply staining, very numerous, and 

 closely packed together. The medial bar, which is the more constant and essential 

 portion of the nuclear complex, presents these cell conditions to the best advantage. 

 These facts, coupled with the finding of great numbers of true spindles to the 

 practical exclusion of other cell types, strengthen the assumption that the spindle- 

 cell is the one peculiar to and characteristic of this nucleus. The lateral masses 

 show the same general cell characteristics, though they are not as regular in the 

 medial mass. While the nucleus is very richly supplied with blood-vessels in all 

 the animal forms, the human nucleus is especially vascular. 



A careful study was made of the cells in the areas adjacent to the superior olive 

 in order to definitely delimit the nuclear mass under consideration. There are 

 several groups of these cells to be considered, and for purposes of description these 

 may be classed as follows: (1) The cells of the nucleus facialis, which, though situ- 

 ated in the f ormatio reticularis, for obvious reasons require specific consideration ; 

 (2) the cells in the f ormatio reticularis; (3) the cells in the corpus trapezoideum. 



(1) The nucleus facialis is a large nuclear mass located in close proximity to 

 the dorso-lateral surface of the superior olive, but the cells making up this nucleus 

 are as characteristic of their kind as are those of the superior olive. These two 

 types of cells differ so widely that confusion is hardly probable, although Weed 

 found it difficult to differentiate the lower pole of the olive from the facial nucleus 

 in the tissue which he studied. A study of the fiber relations of these cells is also 

 an aid in distinguishing them. 



(2) The formatio reticularis presents a great number of cells which are, for 

 the most part, scattered irregularly throughout the brain-stem. At times a few 



