374 SPECIAL HISTOLOGY. 



fibres, which extend from before backwards, in the middle, through the 

 medulla oblorigata, contributing to the formation of the so-termed raphe 

 (Stilling) ; 3, and lastly, of very numerous fibres proceeding from this 

 raplie into the lateral halves of the medulla, following a more or less 

 curved direction. These latter, the interiial transverse fibres, commence 

 behind the pyramids, and the anterior of them as a large mass, very 

 minutely broken up by fine flattened fasciculi of the pyramidal and 

 olivary columns, penetrate from within into the corpus dentatum olivce, 

 the white substance of which is constituted by them ; they then expand 

 in a brush-like form, and are continued through the gray substance of 

 the corpus dentatum, ultimately turning backwards towards the fasciculus 

 cuneatus [corpus restiforme] and lateralis. In this course, the fibres 

 describe larger or smaller curves. The latter is the case with those 

 which come out from the posterior part of the olivary nucleus [^corpus 

 dentatuni\, and which go almost directly backwards and outwards 

 through the accessory olivary nucleus (Stilling), and the gray substance, 

 containing large cells, situated on its exterior; the former condition 

 obtains in the anterior fibres, which spread out in a radiating manner, 

 passing at first forwards between the pyramids and olivary nucleus, and 

 afterwards backwards in a sharp curve, superficially round the latter, 

 into the lateral fasciculi. A second division of the internal transverse 

 fibres goes behind the olivary nucleus with which it has no connection, 

 directly from the raphe, through the posterior part of the olivary 

 columns and the enmientice teretes, outwards and backwards, also into 

 the restiform body. All these fibres, and most of them obviously so, 

 are associated together, and appear to me to be continued from the 

 restiform bodies and the peduncles of the cerebellum, into the anterior 

 divisions of the medulla oblongata. With respect, however, to their 

 more intimate relations, concerning which Stilling's work and my 

 " Microscopical Anatomy" may be consulted, little is as yet known. 



The gray substance, in the medulla oblongata, is collected into lai^ger 

 masses, chiefly in three situations, viz., in the olivary and restiform 

 bodies, and on the floor of the rhomboid fossa (fourth ventricle) : 1, the 

 gray substance of the olivary bodies forms, as is well known, a folded 

 lamella, constituting a capsule closed on all sides except the inner, 

 which, although it occupies the situation of the anterior horns of the 

 spinal cord, Avhich are continued nearly to its inferior border, still has 

 no direct connection with them ; appearing, also, to be otherwise isola- 

 ted from all other gray substance. AVithin it, besides the very numer- 

 ous nerve-fibres of the transverse fibre-system, which traverse it for the 

 most part in straight lines, there occur in great numbers smaller nerve- 

 cells, measuring 0-008-0-012 of a line in diameter, and of a rounded 

 form, with 3-5 branching processes, and containing in the interior yel- 

 lowish granules, to which the color of the olivary bodies is due. The 



