INTERLACEMENT OF THE CEREBELLAR PEDUNCLES. 477 



These fibrse arcuatse proceeding from the corpus restiforme 

 cross the median line (partly running in front of, and partly 

 out of, the hilus of the olivary body), and penetrate the 

 opposite surface of the other olivary body in order to join 

 its nerve corpuscles. The crossed connection of the corpora 

 restiformia with the olivary bodies was admitted by Deiters, 

 on the ground that both olivary bodies contain, in addition 

 to such librae arcuatse as can be shown to be connected with 

 their cells in teased-out preparations, arched fasciculi that 

 simply traverse them. The pathological fact, that atrophy 

 of one half of the cerebellum always coincides with atrophy 

 of the opposite inferior olivary body, supports the same 

 view. The more posterior fibrce arcuatce proceeding from 

 the cells of the olivary body are continued into the cuneate 

 and slender fasciculi (on the opposite side to their cere- 

 bellar origin), curving, after interlacement of their nuclei, 

 around the transverse section of these columns. They augment 

 the size of these columns by degrees to so great an extent 

 that they approximate to one another behind the central grey 

 substance of both sides, till they touch in the middle line on 

 either side of the posterior fissure (fig. 258, Gr). 



2. The most posterior of the fibrse arcuatae which thus pass 

 into the posterior column, it is obvious, cannot be connected 

 with the olivary body on the same side, because the whole of 

 this part of their course from the raphe' to that column lies 

 behind the olivary body. There are circumstances, however, 

 that seem to show that these posterior fibrae^rcuatae have tra- 

 versed the opposite olivary body on the other side of the 

 raphe : for they do not pass transversely across the raphe' , 

 but, in their course from one side of the medulla oblongata into 

 the opposite posterior columns, they pursue a long course, from 

 before backwards, partly within the raphe as fibrae rectae (fig. 

 258, R), partly, before their median decussation, within the 

 transverse section of the anterior column, where they run in 

 a radiating direction from before and outward towards the 

 raphe; so that in their decussating course they really must 

 have passed the region of the olivary bodies. This division 

 of the fibrae arcuatae in particular stands in connection with the 

 large scattered cells of the motor area. Thus the most poste- 



