82 Journal of Comparative Neurology. 



and contiguity, forming such a wicker tissue as to present a 

 labyrinthine and, to the anatomist, completely inexplicable knot, 

 unless nature while living in this intricate abode teaches him to 

 unravel her tissue in the same order in which she herself com- 

 posed it." — Emanuel Swedenborg, 1744. 



"Search after the fundamental lines in the structures of 

 the brain is the present task of the brain anatomist. Once we 

 have accomplished this, it will be easy to understand the com- 

 plicated conditions present in the more highly organized brain," 

 — Edinger (9, vi). 



"The key for understanding the complex brain must be 

 sought in the study of its earliest embryonic stages." — Wilhelm 

 His (16, 348). 



The examination of the adult cerebellum gives absolutely 

 no conception of what the organ was like in its earlier develop- 

 ment. The only way that it can be comprehended is to "see 

 it grow." 



The ectal appearance of the adult organ is that of an oval 

 corrugated mass. The caudal aspect presents an appearance 

 like that of a little hill in a valley between two high mountains. 

 The cephalic aspect is more like that of a long hill in the mid- 

 dle of a plain. The entire surface, plain, hills and mountains, 

 is cut by a perplexing tangle of little ravines and deeper gorges, 

 for the most part parallel, whose beginnings and endings are as 

 bewildering as are the figures of the quadrille to the novice. 



A closer inspection shows that there are lobes separated 

 by deep fissures, and that the lobes in turn are cut into a 

 greater or less number of narrow folia by shallower fissures. 

 These lobes have received special names, many of which are 

 artificial and unscientific. 



But the study of the adult organ can give no better knowl- 

 edge than this. 



If, however, we begin with early embryos and trace the 

 development of the cerebellum to its adult condition, many of 

 the difficulties disappear. 



The writer believes this method to be the soundest one 



