i 4 8 COMPARATIVE PHYSIOLOGY OF THE BRAIN 



segmental standpoint, we imagine the role of the 

 central nervous system to be similar to this : the 

 various elements or ganglia take the place of the re- 

 tinal elements in the perception of forms. The same 

 elements or ganglia participate in many " functions." 

 Every element shares in the result according to the 

 location of the segment, and other general or special 

 qualities. But if we attempt to make clear to our- 

 selves how the retina should act according to the 

 centre-theory, we find that every retinal element 

 would have to serve for the perception of one image 

 only, that we could see only as many different images 

 as we have retinal elements (for instance, rods). We 

 do the centre-theory no injustice in making this com- 

 parison : its consistent representatives really assume 

 that each image of memory is deposited in a special 

 cell, that the number of the cells of the brain de- 

 termines the number of the images of memory which 

 are possible. 



I wish to call the attention of the reader to the fact 

 that Dr. A. Meyer has arrived, independently, at simi- 

 lar conclusions concerning the segmental character of 

 the central nervous system of Vertebrates as those set 

 forth in this chapter (9). 



BIBLIOGRAPHY. 



1. GOLTZ. Ueber die Functionen des Lendenmarks des Hundes. 

 Pfliigers Archiv, Bd. viii., 1874. 



2. GOLTZ. Beitrdge zur Lehre von den Nervencentren de& 

 Frosches. Berlin, 1868. Verlag von Hirschwald. 



