The 



Journal of Heredity 



(Formerly the American Breeders' Magazine) 



Vol. IX, No. 1 January, 1918 



CONTENTS 



The Grafted Jujube of China, by David Fairchild 3 



Outline of Applied Sociology (Review of a Book by Henry Pratt 



Fairchild) 7 



Tracing Your Ancestors 8 



The Origin and Evolution of Life (Review of a Book by Henry Fair- 

 child Osborn) 14 



Petalization in the Japanese Quince, by Albert A. Hansen 15 



An Introduction to Social Psychology (Review of a Book by Charles 



A. Ellwood) 17 



Colors in Vegetable Fruits, by Byron D. Halsted 18 



The Cause of Mongolian Imbecility 23 



Introduction of Insect Pests to be Avoided 23 



Unusual Variation in Crook-Neck Squash 24 



Evolution by Hybridization, by E. C. Jeffrey 25 



The Influence of Heredity in Diabetes 28 



SoiTie Variable Ears of Dent Corn, by A. D. Shaniol 29 



Organic Evolution (Review of a Book by Richard Swann Lull) 32 



Alcohol as a "Racial Poison" 32 



Color Inheritance in Mammals; VIII, Swine, by Sewall Wright 33 



Sex Ratio in Cattle Cannot be Controlled 38 



Extra Toes in Horse and Steer, by B. O. Severson 39 



A Test for Supermen 42 



Delinquent Dullards 44 



Feeblemindedness in Delaware 15 



More Remarkable Button-Balls 48 



The Journal of Heredity is published monthly by the American Genetic 

 Association (formerly called the American Breeders' Association) for the benefit 

 of its members. Canadian members who desire to receive it should send 25 cents 

 a year, in addition to their regular membership dues of $2, because of additional 

 postage on the magazine; foreign members pay 50 cents extra for the same 

 reason. Subscription price to non-members, $2.00 a year, foreign postage extra; 

 price of single copies. 25 cents. 



Entered as second-class matter February 24, 1915, at the postoffice at Washing- 

 ton, D. C, under the act of August 24. 1912. Contents copyrighted 1917 by the 

 American Genetic Association. Reproduction of articles or parts of articles 

 permitted provided proper credit is given to author and to the Journal of Heredity, 

 (Organ of the American Genetic Association), Washington, D. C. 



Date of issue of this number, December 28, 1917. 



