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Nachdruck verboten. 



The Tuberculum olfactorium. 



By G. Elliot Smith. 

 With 2 Figures. 



On the ventral aspect of the cerebral hemisphere in most mammal- 

 ian brains there may be seen midway between the cerebral attach- 

 ment of the pecluuculus olfactorius and the optic chiasma a rounded 

 cap of irregular grey matter, which has been commonly known as the 

 "tuberculura olfactorium", since v. Koelliker applied this term to it 

 in the year 1894 1). 



So far as I can learn, however, the term "tuberculum olfactorium" 

 was originally applied by Gegenbaur to a totally different structure 



— the swollen cerebral attachment of the pedunculus olfactorius, which 

 is now known by the name "trigonum olfactorium", introduced by His, 



As the name implies, it has been commonly assumed to be ol- 

 factory in function, although no definite demonstration has yet been 

 forthcoming of the path by which smell-impulses coming from the ol- 

 factory bulb reach the olfactory tubercle, v. Koelliker 2) states that 

 the fine fibres found upon the surface and amongst the "islotes ol- 

 fativos" of Calleja are considered by the latter to be derived most 

 probably from the bulbus olfactorius and to pass to the tuberculum 

 by way of the mesial olfactory tract. 



After a searching examination of the whole problem Ramon y 

 Cajal has recently summarised his views on this subject as follows : 



— "I am quite unable to answer the difficult question whether any 

 fibres springing from the olfactory bulb penetrate into the tuberculum 

 olfactivum. In MARCHi-preparations made after extirpation of the 

 bulb it has been impossible to find any degenerated fibres in the plexi- 

 form layer of the tuberculum. In fact, up till the present time no 

 entry of either secondary or tertiary olfactory paths into the tuber- 



1) Ueber den Fornix longus von Forel und die Riechstrahlungen 

 im Gehirn des Kaninchens. Verhandl. der Anat. Gesellschaft. 



2) Handbuch der Gewebelehre, Bd. 2, 1896, p. 725. 



