92 



The Journal of Heredity 



•group; and in our observations of 150 

 to 200 varieties, the varieties of this 

 -group rarelv form multiple fruits. The 

 remainder are of the so-called Persian 

 or Crawford group or are inter-group 

 liybrids. In normal years, more double 

 fruits are seen on varieties such as 

 Foster, St. John and other closely re- 

 lated varieties of the Persian or Craw- 

 ford group, and our observations show 

 tliat the majority of thsse are probably 



formed from twin flowers rather than 

 from single flowers with double pistils. 

 The causes of this phenomenon may 

 be many. The tendency seems to be 

 hereditary among a certain group of 

 varieties. The occurrence would seem 

 to be due to environmental conditions 

 and any environmental factor or com- 

 bination of factors which would tend to 

 bring about doubleness would cause 

 this multiplication. 



When To Marry 



The age at which one should marry 

 presents a problem with so many 

 sides that any simple solution of it 

 is out of the question. But it is a 

 question on which every one holds 

 a definite opinion; so the Umschau, a 

 German weekly devoted to popular 

 science, is likely to find many con- 

 testants for prizes aggregating 40,000 

 marks, which it offers for the best 

 brief essay on the subject. It de- 

 sires that the question be considered 

 from the points of view of genetics, 

 hygiene, psychology and psychiatry, 

 -either collectively or singly. Judges 

 of the contributions are Max von 

 Gruber, Professor of Hygiene in the 

 University of Munich, and one of the 

 leaders of the eugenics movement in 

 Germanv; Valentin Haecker, a well- 



known geneticist at the University of 

 Halle ; and H. Bechhold, of Frank- 

 fort am Maine, editor of the Um- 

 schau. 



From France, at the same time, 

 comes a partial attempt to answer the 

 question, in a paper by Dr. Paul 

 Godin, which occupies the leading 

 position in the second number for 

 1922 of Eugcnique, the organ of the 

 French Eugenics Society. Dr. Godin's 

 study, entitled "Eugenique et Puberte," 

 leads to the conclusion that on the 

 average, a woman is physiologically 

 ready for marriage at eighteen and a 

 half years, a man two years later. 

 The data on which these conclusions 

 are based are far from conclusive, 

 however. 



Lives of Fossil Animals 



Lebensbilder aus der Tierwelt der 

 VoRZEiT, by Othenio Abel, Pro- 

 fessor of Paleontology at the Uni- 

 versity of Vienna. Colored front- 

 ispiece and 507 text figures. Pp. 

 631). Jena, Verlag von Gustav 

 Fisher, 1922. 



Paleontology has played an impor- 

 tant part in forming the general doc- 

 trine of evolution, and paleontologists 

 have not hesitated to draw precise 

 conclusions involving somewhat de- 

 tailed points of genetics — conclusions 

 which most geneticists have been in- 



clined to challenge, on the ground that 

 the fragmentary documents afforded 

 by fossils are not detailed enough to 

 warrant precise conclusions. Never- 

 theless, every contribution from the 

 realm of prehistoric animals is wel- 

 come to the student of heredity, and 

 the lavishly illustrated volume by Dr. 

 Abel is particularly attractive. The 

 author's plan is to give a detailed de- 

 scription of the life of ten dififerent 

 periods, regarding which the extant 

 evidence is fairly abundant. Three 

 of the regions considered are in the 

 United States. —P. P. 



