AUTHOE'S PEEFACE TO THE FIFTH GEEMAN EDITION. 



Not without a certain hesitation does the author come with this edition 

 before his circle of readers. Though the previously small book has now 

 grown to larger proportions, still it presents a subject which has not pre- 

 viously been comprehensively treated: the comparative morphology of the 

 central nervous system. 



T'hree parts have arisen from the original little work: parts which 

 are so far independent of each other that they who have less interest 

 for the more general matters and for comparative anatomy, by ttirning 

 past the first two parts will find in the third a somewhat enlarged and 

 richly-illustrated edition of the old book. Grateful for the interest which 

 the medical profession have manifested in the work, the third part, which 

 deals exclusively with the mammalian, and especially with the human, brain, 

 has been carefully rewritten and enlarged through the addition of numerous 

 figures made from photographs of sections. In order to facilitate the study 

 from sections a complete series of frontal sections through the entire brain 

 has been added. 



Part I is introductory, giving the fundamental ideas accepted at the 

 present time. It takes into consideration also function, which was not con- 

 sidered in earlier editions. 



The second part of the book realizes finally a plan which, since the be- 

 ginning of my studies in brain-anatomy, I have never allowed to escape my 

 eye. Eesting almost completely upon my own investigations, it gives a 

 review of that which may be said, with some certainty, of the structure and 

 course of development of the central nervous system in the vertebrate series. 

 Those who have worked in this field, still cultivated, will, considering the 

 difficulties which tower up everywhere, leniently judge that which is prof- 

 fered. The first attempt at a general presentation, the book shows every- 

 where the insufficiencies which such a work must present. No one knows 

 that better than the author himself. If, as here, the plan of the whole 

 forbids going into details, it will not be possible to always give a sufficient 

 foundation for that which is presented. So far as it has been possible, this 

 has been supplied in the numerous figures whose addition has been made 

 possible through the liberality of the publishers. This edition contains 113 

 figures more than the Fourth, and of the new ones, 99 are devoted to com- 

 parative anatomy. The central nervous system has formerly been studied 



