Literafy Notices. cxv 



(b) Vagus. The large dorsal nidulus of the vagus lies close to 

 the ventricle on each side, extending for a considerable distance from 

 the end of the cord cephalad. Its cells are of two kinds, large, blad- 

 dery cells, deeply staining with carmine, and small, faint multipolar 

 cells. The fibres passing from this nidulus, emerge in a line which 

 passes from a point just cephalad of the emergence of the dorsal root 

 of the first cervical ventro-cephalad to the lateral aspect of the medul- 

 la, just caudad of the emergence of the glossopharyngeal. 



In addition to this dorsal nidulus there is the ventral nidulus al- 

 ready mentioned in connection with the accessorius. The fibres of 

 the vagus upon entering the medulla pass to the dorsal nidulus, and 

 divide into two tracts. One terminates in this nidulus, the other con- 

 tributes some fibres to the ventral nidulus, while others pass farther 

 mesad to the dorsal part of the raphe in which they cross and pass 

 ventrad until they reach the ventral bundles of the opposite side. 

 None of these crossed fibres could be traced to cells. 



There is a small but distinct bundle of fibres which passes ventrad 

 from the dorsal nidulus, part to join the dorsal end of the raphe, part 

 however, crossing the dorsal fibres of the latter and going over into 

 the formatio reticularis. The connection of the dorsal nidulus of the 

 vagus with the higher centres is to be sought in these fibres. 



Thus the vagus proper consists of three parts, the largest of 

 which arises from the dorsal nidulus. The origin from this nidulus 

 was demonstrated experimentally by two methods, (i) In two doves 

 just hatched the vagus was cut on one side in such a way as to leave 

 the ganglion. After six and eight weeks respectively, the vagus root 

 was found in both cases to be thinner, and the dorsal nidulus much 

 smaller than on the other side. Moreover, the cells were less sharply 

 defined, were less susceptible to carmine, their nuclei were smaller 

 and the intervening fibres were more sparse and presented a pale and 

 varicose appearance. (2) The coloring of degeneration products by 

 Marchi's method was applied to the crow. Two adult specimens 

 were deprived of the nerve on one side without destroying the gang- 

 lion. After six weeks they were killed and the medulla, together with 

 the vagus ganglion, was cut into serial sections and stained. Peripher- 

 ally from the ganglion the fibres were degenerated and filled with black 

 lumps. A few degenerate fibres passed through the ganglion. The 

 cells of the latter seemed to be intact. Centrally from the ganglion 

 the degenerate fibres again were plainly visible and could easily be 

 followed to the point where the vagus tract divides. From this point 

 on, the fibres which pass to the dorsal nidulus were very frequently 



