Xll CONTENTS 



PAGE 



V. Circulation no 



The Heart and Circulation 



A. J. Carlson mid V. Johnson no 



Your Heart . . 



Metropolitan Life Insurance Compafiy and American 



Heart Association 123 



VI. Nervous and Endocrine Control of the Body . , , . 134 



The Background of Human Mentality Ralph Linton 135 



The Endocrine Control of the Body . Michael F. Giiyer 141 



VII. Reproduction 154 



Reproduction Emanuel Rddl 155 



Sex Michael F . Guy er 159 



VIII. Embryology 168 



Embryology Leslie Brainerd Arey 168 



Embryology and Genetics . . Thomas Hunt Morgan 172 

 Old Problems and New in Experimental Embryology . 



E. G. Butler 178 



IX. Heredity 188 



Gregor A4endel and His Work .... Hugo litis 189 



Human Heritage Carroll Lane Fe?it07i 195 



The Study of Human Heredity . Laurence H. Snyder 199 



What Will Your Child Look Like? . Amraju Scheinfeld 206 



What Blood Tells David C. Rife 211 



The Inheritance of Disease .... Paul A. Lewis 215 



X. Eugenics 227 



Some Bearings of Genetics on Human Affairs .... 



Otto L. Mohr 228 



The Role of Eugenics .... Ed-win Gratit Conklin 232 



XI. Evolution 237 



The Age of Homo sapiens . . . . W. W. Howells 237 



Man's Long Story Lewis G. Westgate 243 



What We Do Not Know About Race 



Wilto?! Marion Krogman 255 



XII. Ecology 267 



Interdependence of Plants and Animals . . A. S. Pearse 268 



