110 C. WINKLER. THE CENTRAL COURSE 



and the ,,aberrirendes Seitenstrangbiindel" (Plate XXII fig. 28 C) 

 also has. Those different layers are forming the lateral fillet. 



As soon as the contact with the cerebellum is lost, and the 

 bracchia pontis surround the basis mesencephali (Plate XXII 

 fig. 28 F) a very interesting aspect is found. 



At the side of the operation, most superficially, laterally from 

 the pedunculus cerebelli superior, separated from it by the dorsal 

 nucleus lemnisci, the ventral ascending spino-cerebellar tract lays. 

 Only for a moment, for it distally retires to the cerebellum in the 

 nuclei tecti, and proximally (Plate XXII fig. 28 F) it gives its 

 fibres to the ventral part of the tegmentum. This tract has lost 

 here many fibres on the operated side, and is much smaller than 

 that on the contra-lateral side. 



But more interesting is the loss of fibres found now in the ventral 

 parts of the lemniscus at the contra-lateral side (Plate XXII fig. 28 F). 

 The nucleus ventralis lemnisci is atrophied. It has not only lost many 

 fibres, but also a great many cells and they are much smaller than 

 at the operated side. Its surroundings, still adjacent to its lateral, dorsal 

 and ventral borders have lost fibres and are intensely atrophied. 



There is an absolute ressemblance with the drawings of the 

 MAR CHI-degeneration, where these surroundings (the shell of the 

 acorn) are degenerated (fig. XIX, XX fig. 25 A G fasc. later. 1. 1.) 



But medially from the nucleus ventralis lemnisci there appears 

 another layer of fibres, on which the ventral end of the bracchium 

 conjunctivum cerebelli reposes. This layer a continuation of the 

 dorsal olivary surroundings has lost a great many fibres. If com- 

 pared with the MAiiCHi-degeneration , the degenerate fibres found 

 medio-dorsally and dorsally from the contra-lateral nucleus ventralis 

 lemnisci are now intensely atrophied (on both sides in Plate XIX, 

 XX fig. 25 A F fasc. med. 1. 1. y and Plate XXII fig. 28 F). 



These two layers - - the fasciculus medialis lemnisci and the fasci- 

 culus lateralis lemnisci - - embrace the nucleus ventralis lemnisci. 

 They pass into the more internal layers of the lateral fillet, whose 

 lateral surface remains free from degeneration or atrophy. They 

 surround the distal pole of the corp. quadrigeminum. This part of 

 the ganglion is atrophied - - with GUDDEN'S method - - to a consi- 

 derable degree. With MARCHi-method there also intense degene- 

 ration is found. A great many of the degenerate fibres however 

 remain in the nucleus ventralis lemnisci and (Plate XIX fig. 25 

 B G) the lateral layers round this nucleus, entering in internal 

 layers of the fillet, are less intensely degenerated than those situated 

 medially from it. 



