( 300 ) 



Without any doubt these disturbances are dependent on that hearth. 



The loss of hearing is probably connected with the destruction of 

 the corpus geniculatum mediale. This destruction, together with the 

 secondary atrophy towards the temporal radiation (see a, in the 

 figures), suffice to explain a certain loss of hearing, according to 

 experiments made by different investigators after very different methods. 



It is only to be noted as a remarkable fact that the patient was 

 at first completely deaf on both sides, although the lesion was onl\ 

 at the left side. Remarkable too is the rapid way in which an im- 

 portant amelioration of this deafness set in. 



The area of degeneration (a, in the figures) does not attain in the 

 first place the medullary cone of the temporal convolution turned 

 towards the fissura Sylvii, but is situated in preference in the two 

 other temporal convolutions. This may be a reason, that she did 

 hear and understood the spoken word. 



It is formed by degenerated fibres, arriving thither both from the 

 stratum sagittale externum and from the stratum sagittale internum, 

 as becomes evident especially in the more frontal sections. In the 

 sections made more caudalwand, a degenerated fascicle going towards 

 the splenium corporis callosi may also be pursued. 



Perhaps these facts may add something to an eventual explanation 

 of the incomplete deafness on both sides after focal disturbances on 

 one side of the brain. But leaving this aside as less important, we 

 desire only to call attention to the chief point of this interesting case. 



The ventral groups of nuclei in the thalamus opticus, more especi- 

 ally their caudal portions and these nuclei only, with the exclusion 

 of all others are found softened in the cerebrum of <i person, 

 who during life hod lost "// sensibility in the distal ends of the, 

 crossed extremities vilhout choreic movements, without intensive cortical 

 ataxy on that sole, whilst the sensibility remained nearly intact in the 

 face, and had suffered some decrease at the proximal ends of extremities. 



Similar strictly defined hearths of degeneration are very rarely 

 found in hemi-anaesthesia, but they contribute important data to the 

 study of the intra-cerebral course of the tracts for the general sensibility. 



These tracts are less known by far than the intracerebral course 

 of the tracts for sight and hearing. 



Since TüRCK in 1850 by his experimental researches gave the first 

 impulse to the study of the intra-cerebral sensibility tracts, there has 

 appeared an enormous amount of literature on this subject, which has 

 been recapitulated with sufficient accuracy in the dissertation of 

 Long 1 ) (under guidance of Dëjérfne). The chief result of this mass 



l ) Edouakd Lung. Les voies centrales de la sensibilité générale. (Etude Anatomo- 

 cliuique). These de Paris. 1899. 



