vi PREFACE TO THE TENTH EDITION 



in two respects. The description of the cerebellum and its func- 

 tions is introduced before the account of the cerebrum, instead of 

 after it as in the former presentation. The chapter on the auto- 

 nomic system has been rewritten, with special emphasis on the 

 "emergency " function of the system. The relation of the hormone 

 adrenin to the autoriomic system is discussed. In connection with 

 the section on respiration the effect of muscular exercise on the 

 respiratory function is given fuller consideration. In the chapter 

 on foods the paragraphs dealing with dietary accessories are elab- 

 orated. The recent work on the relative food values of various 

 proteins is described at some length. The conception of basal 

 metabolism is introduced as a ground work for the discussion of 

 general bodily metabolism. In the chapter on reproduction para- 

 graphs dealing in an elementary way with Mendelian inheritance 

 and the mechanism of sex-determination are included. In response 

 to requests from several users of the book an appendix containing 

 suggestions for laboratory experiments suitable for undergraduate 

 classes is added. The basis of these is the laboratory course given 

 for several years to undergraduates at Harvard and Radcliffe 

 Colleges. 



I beg to acknowledge the receipt of helpful suggestions from 

 various colleagues. Among these I wish to mention especially 

 Professor Chas. Wright Dodge, who very kindly furnished me a 

 detailed list of comments based on his use of the former edition 

 in his classes during a period of years. 



A number of new cuts have been introduced. Some of these 

 were drawn especially for this edition. Others were kindly fur- 

 nished by the publishers of various text-books. I desire to make 

 acknowledgment of this courtesy. 



ERNEST G. MARTIN. 

 STANFORD UNIVERSITY, CALIF. 



Jvly, 1917. 



