CHAPTER I. 



Eetiew op the History and the Methods op Investigation of 

 THE Central Xervous System. 



The anatomy of the central nervous system, whose features these 

 chapters are to present, has, since the renaissance of anatomy, engaged the 

 lively interest of numerous investigators. Vesalius, Eustachio Aranzio, 

 Variolo, and Fallopia laid the foundations upon which, in subsequent 

 centuries, the superstructure could be built. Even in the seventeenth 

 century there appeared extensive monographs, which, considering the tech- 

 nique at command at that time, must be recognized as practically exhaust- 

 ive: e.g., the books of Th. Willis and of Raim, Vieussens. Nevertheless 

 Willis could still describe as new such structures as the corpus striatum, the 

 anterior commissure, the pyramids, and the olivary bodies. Important con- 

 tributions on brain-anatomy were made even at that time by Sylvius, 

 Wepfer, and Van Leeuwenhoek, the last of whom was first to make a 

 microscopic investigation of the brain. Malacarne, in Italy; von Soemmer- 

 ing, in Germany; Vicq d'Azyr and Eolando, in France, contributed much, 

 in the latter part of the eighteenth century, to the extension of our knowl- 

 edge of the brain. 



As our century dawned there was scarcely anything of importance to 

 be added to the gross anatomy of the organs of the central nervous system. 

 Little progress had been made, however, in what we must now recognize 

 as the most important part of the morphology of the central nervous system, 

 namely: in the knowledge of the finer relations of the parts, — of the course 

 of the fibers. Even investigations in the comparative anatomy which were 

 made in the first decades of the nineteenth century made no advance in 

 this field. What remained to be done by essentially macroscopic methods 

 has been accomplished by Eeil, Gall and Spurzheim, Arnold, Eeichert, 

 Foville, Burdach, et al. 



Eeil, in particular, who first brought into general recognition as a 

 preparatory method the artificial hardening of the brain, had discovered 

 a great many facts which do not appear upon the surface. 



As his most important discovery one must designate the boundary of 

 the corona radiata and the pedunculi cerebri, whose relation to the corpus 

 callosum, which traverses them, he first recognized; the Tractus tecto- 

 spinalis and its origin in the Corpora Quadrigemina, the Nucleus lenti- 



(3) 



