"2 LECTURES ON THE CENTRAL NERVOUS SYSTEM. 



century, added nothing to this knowledge. Whatever it was 

 possible to discover by the coarse, macroscopic methods of in- 

 vestigation was discovered by Reil, Gall and Spurzheim, F. 

 Arnold, C. B. Reichert, Foville, Bnrdach, and others. 



Reil, in particular, who first brought into general use the 

 process of artificially hardening the brain, discovered a number 

 of anatomical facts, which were the result of closest observation. 

 As his most important discoveries must be reckoned the arrange- 

 ment of the corona radiata, the nerve-tracts of the crus cerebri, 

 whose relation to the fibres of the corpus callosum, which pass 

 transversely through it, he was the first to recognize. The 

 lemniscus and its origin in the corpora quadrigemina, the len- 

 ticular nucleus, the island, and many other parts were first 

 made known through his investigations. As a landmark at the 

 end of this older period, we may regard Burdach's work on 

 "The Structure and Life of the Brain," which appeared in 1819 

 and contained all that had been discovered up to that time, be- 

 sides adding much new material. 



Up to about the middle of this century the most prominent 

 methods of investigation were anatomical dissection with the 

 knife and teasing out fibres from hardened specimens of brain 

 with forceps. By the latter method Gall, Burdach, Reil, F. 

 Arnold, and Foville discovered much that was new. To Tiede- 

 mann and Reich crt is due the chief credit of introducing the 

 study of embryology, from which we have learned much con- 

 cerning general morphological conditions. 



But after Ehrenberg (1833) proved that "the organ of 

 mind" 1 consisted of innumerable microscopic "tubules;" after 

 Remak (1838) had given a more accurate description of the 

 ganglion-cells, and Hannover (1840) had shown their connec- 

 tion with the nerve-fibres, it was plain that a simple process of 

 teasing could never give the desired insight into the structure 

 and arrangement of the central nervous system. To B. Stilling 

 is due the great credit of originating and bringing into use a 

 .new method, viz., the preparation of thin sections, or, rather, of 



