Literary Notices. cxix 



In conformity with this hypothesis it has been claimed that degen- 

 eration does not proceed centrad in the case of centrifugal nerves. 



The investigation of the central system of those who had suffered 

 amputation, showed that changes actually go on in the central stump and 

 cord. Vulpian was the first to investigate the effects many years after 

 amputation. He found considerable diminution in the size of the cor- 

 responding half of the cord, especially in the segment from which the 

 nerves arise. Vulpian recognized simply a thinning without histological 

 alteration of the nerves, and in' the cells there was nothing abnormal. 

 Dickson, Hayem, and others noticed diminution in number of the cells 

 of the ventral cornu and obvious indications of degeneration. Fried- 

 lander and Krause state that it is only in the lateral group of the ventral 

 cornua that this diminution takes place and especially call attention to 

 the reduction of dorsal columns and cord and loss of cells in Clark's col- 

 umns. It was concluded that the effects are due directly or indirectly to 

 degeneration in the sensory paths. 



The experimental researches of v. Gudden and his school have added 

 much to the solution of these problems. The method consists in the 

 eradication of nerve roots in new-born animals. 



Meyser removed the sciatic nerve with its spinal ganglia and noticed 

 reduction of the gray matter, especially of the dorsal cornu. The ventral 

 cornu lost its definite boundaries and exhibited obvious degeneration 

 phenomena. 



Removal of the seventh nerve produced atrophy of the lowar facial 

 nidulus. Eradication of the nerves of the eye muscles produced atrophy 

 of the niduli of III, IV and VI, while section of the XII nerve destroyed 

 the large-celled hypoglossus nidulus, but not that of Roller. 



The vagus has also been operated on with more or less definite re- 

 sults. [See Vol. I, p. XXVI.] 



Even in adults, as Nissl has shown, 24 hours after eradication of the 

 facial, histological changes occur in the cells of its nidulus. The chro- 

 matin body decomposes in part of the cell. After six days the protoplas- 

 mic structure is lost. [For recent studies see Vol. II, p. liii.] 



The author's work may be thus summarized : 



Out of six cases where the facial was removed, every root fibre de- 

 generated on the operated side. There is no evidence of a partial decus- 

 sation of this nerve. The fibres connecting facialis and raphe do not 

 degenerate. 



