PREFACE xiii 



able and sympathetic assistance of Mrs. Alice G. Margulies, whose eflorts 

 in assembhng the bibliography have provided valuable addenda for those 

 desiring further references to the literature. 



To make due acknowledgment for all of the assistance I have received 

 would necessitate setting forth a long list of my friends and associates. 

 Among these, however, I cannot fail to mention Mr. Frank N. Doubleday, 

 whose invaluable advice has led to many important revisions in and addi- 

 tions to the text. 



It also gives me great pleasure to mention the indispensable services of 

 Miss Regina linger in preparing the serial sections of the primate brains 

 upon which this study is based. Miss Unger has for a number of years been 

 engaged in the technical production of brain series, particularlv Pal-Weigert 

 preparations, which constitute one of the most highly valued accessions of 

 the Neurological Department in Columbia University. Without these speci- 

 mens, neither the microscopic nor reconstruction studies would have been 

 possible. 



In the preparation of the illustrations and text for publication, Miss 

 Florence Fuller of the publishers' staff has given most enthusiastic and 

 helpful attention. 



And, finally, to my publisher, Mr. Paul B. Hoeber, I wish to acknowl- 

 edge my deep indebtedness for his generosity and for the encouragement and 

 unfailing inspiration which he has given me at all times. 



F. T. 



New ^'ork, N. Y. 

 March, 1928. 



