Literary Notices. xxix 



The Fornix. 



The detailed and minute work of Honnegger on the fornix is not 

 susceptible of a compendious resume. It will remain for years the source 

 of information in this difficult portion of the brain. Unfortunately the 

 present work is not calculated to render the subject much more perspicu- 

 ous. It may be some time before comparative and embryological data are 

 at hand to enable us to distinguish the essential from the non-essential, the 

 valid from the spurious, in the vast collection of facts and views here pre- 

 sented. There can be no doubt that many of the connections resting on 

 observation of adult material will be shown to have a quite different sig- 

 nificence from that now attributed to them. 



The Tectum Optici'm, Etc. 



Cajali states that in all vertebrates the optic nerve fibres terminate 

 in free branches is the optic centra. Numerous fibres of the optic nerve, 

 however, end in the corpus geniculatum and surrounded with their 

 branches the cells of this body. Three categories of cells occur in the 

 gray matter of the corpora quadrigemina, of which apparently one sort 

 seiids fibres toward the retina. (From the present writer's observations in 

 fishes as well as the studies of Belonci in other groups it may be inferred 

 that the fibres observed in the geniculata pertain to the inferior commis- 

 sure system rather than true optic fibres) . Our own observations in young 

 fishes (see elsewhere in this number) strongly support the statements of 

 His that the earliest optic fibres are formed as outgrowths of tectum neu- 

 roblasts whose apices pass peripherad.'- 



PosTERioR Commissure. 



The studies of Edinger upon the posterior commissure and lemniscus 

 form the subject of a preliminary notice in Archiv f. Psyckiatru, XXII, 

 1890. The posterior commissure is regarded as one of the oldest systems 

 in the brain. The commissure of the tectum (.Sylvian) is distinguished 

 from the postcommissure. 



Degeneration of Geniculatum. 



Monakow has shown that destruction of the temporal lobe produces 

 degeneration of the corpus geniculatum internum in man as well as in 



1. Terniinacion denervo upticoen his ciif rpos gcnicuhulos y tuliorciilis cuadrige- 

 minos. Gaz. san. niunicipal. 



2. Histogenese u. Zu.saiunienhang der Nerveiiek'iiu'nte. Arch. f. Xiva\. w. PFivk. 

 Supl. Baud, ISyO. 



