No. 3, January, 1922] GENETICS 161 



1052. Forbes, A. W. Education and the size of families. Jour. Heredity 12: 190-191. 

 1921. — The author advances an economic theory in explanation of the small families among 

 college graduates and other educated people. The colleges increase the income of older 

 people, but decrease the income of young people. The standard of living depends largely on 

 the income of the parents. "The condition most favorable to large families is an income 

 of the sons equal to that of the parents at as early an age as possible. At present this condition 



is met among those of inferior parents It is farthest from being true among 



those with the best inheritance, and the colleges are largely responsible for the condition." — 

 Howard J . Banker. 



1053. GoETZ, E. Tabakanbauversuche. [Tobacco culture investigations.] Badisches 

 Wochenbl. 1919 : 67-69. 1919. — The yield of pure lines of tobacco is compared with that of the 

 Fi hybrids of the lines. The mean of parental lines is usually lower than that of Fi hybrids. 

 In some cases the Fi exceeded that of the higher-yielding parent. [From anonymous Abstract 

 in Zeitschr. Pflanzenzucht. 7: 35. 1919.]—/. P. Kelly. 



1054. Grantham, J., and M. D. Knapp. Field experimentation with Hevea brasiliensis. 

 Arch. Rubbercultuur 2: 614-630. 1918. — Yields are given from a large number of individual 

 trees for a period of 12 months. From these data conclusions are drawn concerning the probable 

 error which must be applied in interpreting results of field trials. The error calculated on a 

 tree basis is lower than that calculated on an area basis. The error is not reduced by continuing 

 the experiment longer than 6 months. The use of square plots is advised. No increase in 

 accuracy results from using a plot of more than 100 trees. The theoretical reduction of error by 

 duplication of plots is secured up to the 8 duplications made in the experiment. More than 

 10 or 15 duplications are generally inadvisable. A probable error of 6 per cent may be used for 

 100 tree plots. A precision of less than 5 per cent is not considered practical. [See also Bot. 

 Abets. 10, Entry 1037.]— CarZ D. La Rue. 



1055. Harlin, Ralph G. A case of inherited syndactyly in man. Jour. Heredity 11 : 334- 

 335. 1 fig. 1920. — A type of syndactyly taking the form of a partial webbing between the 

 2nd and 3rd toes occurs in a man, his only son, and 3 of the son's 6 children. The subjects are 

 members "of an old New England family whose genealogy has been fully investigated and 

 published." Despite the fact that this man was one of 10 children, and his presumably normal 

 father one of 6, the trait does not occur in any of the collateral lines. Since the degree to 

 which the trait is manifested is variable the author suggests that it may often pass unnoticed. 

 — C. H. Danforth. 



1056. Harris, J. Arthur, Wm. F. Kirkpatrick, A. F. Blakeslee, D. E. Warner, and 

 L. E. Card. The egg records of limited periods as criteria for predicting the egg production of 

 the white leghorn fowl. Genetics 6: 265-309. 10 diagrams. 1921. — By mathematical formulae 

 derived from the egg records of hens entered at the Storrs Contest 1911-1917, the authors were 

 able to predict with fair accuracy the annual egg record of any hen in the contest when the 

 record for 1 month was known. A 2-month record gave slightly greater accuracy to the 

 prediction. The formulae could also be used on whole flocks of the same breed, but longer 

 periods gave more decided improvement in the accuracy of the predictions. In either case 

 the hens were kept under essentially the same conditions throughout the time the testa 

 were carried out. — H. G. May. 



1057. Hendrickson, A. H. Inter species pollination of plums. Proc. Amer. Soc. Hort. 

 Sci. 16: 50-52. 1919 [1920].— The varieties used were Burbank (Prunus triflora), Heine Claude 

 (P. domeslica), German Prune (P. domesiica), and Shropshire (P. insititia). Results at the 

 second examination, June 12, were as follows: In Burbank, 2281 open-pollinated flowers set 

 1.2 per cent; 150 flowers selfed set 0.0 per cent; 316 flowers X Reine Claude set 5.4 per cent. 

 In Reine Claude, 3505 open-pollinated flowers set 7.1 per cent; 312 flowers selfed set 12.8 per 

 cent; 322 flowers X Burbank set 0.6 per cent; 488 flowers X German Prune set 13.8 percent. 

 In German Prune, 3496 open-pollinated flowers set 20.0 per cent; 426 flowers selfed set 0.0 



