1 00 GENETICS [Bot. Absts., Vol. IV, 



7 fig. Upsala. 1919. — In the first part of this paper are given some facts concerning heredity 

 in general. Pedigrees of a Swedish family with Polydactyly, and the "Lister" family with 

 progressive myoclonous epilepsy are demonstrated. — In the last part author gives an account 

 of racial qualities of the Swedish people. By examination of men in the military service he 

 has found that the length of body is still increasing. In the year 1887 the length was in aver- 

 age 169 centimeters and in 1914 it was 172 cm., which means an increase of a good millimetre 

 per annum. Mortality of children is less and average duration of life is greater than in the 

 other countries of Europe. Author points out the difference between influence of circum- 

 stances and hereditary constitution. — The principles of practical eugenics, different kinds of 

 contra-select ion, the problem concerning increase of population from race-biological point 

 of view, also negative and positive eugenics, are all treated in a competent and interesting 

 manner. — K. V. Ossiaii Dahlgren. 



618. Ibsen, Hem ax L. Linkage in rats. Amer. Nat. 54: 61-67. Jan. -Feb., 1920. — Pre- 

 sents evidence indicating that three pairs of alternative characters in rats, viz., agouti vs. 

 black, self vs. hooded, and black-eyed vs. red-eyed, are inherited independently of each other. 

 In crosses involving red-eye and the pair color vs. albinism, there were no crossovers among 

 seventy gametes, agreeing well with Castle's result of one apparent crossover among 434 gam- 

 etes. — Sewall Wright. 



619. Janskv axd Myslivecek. Beitrag zur familiaren amaurotischen Idiotie. [Contri- 

 bution to familial amaurotic idiocy.] Arch. Psychol. 59: 1918. 



620. Jones, D. F. Hybrid vigor and its meaning. Sci. Amer. 121: 230-231, 239-241. 7 

 fig. 1919. — At the Connecticut Agricultural Experiment Station maize has been artificially 

 self-sterilized for thirteen consecutive years. The outstanding results have been a decided 

 drop in productiveness of grain, a decrease in size and a lessened ability to withstand unfavor- 

 able conditions. At first, many undesirable kinds of plants were observed; but plants incap- 

 able of reproduction ceased their appearance after about 6 generations of self-fertilization, and 

 the remaining inbred plants reached a point beyond which there was no further reduction in 

 size and vigor or alteration in structure. In the process of inbreeding a large number of de- 

 cidedly unfavorable characters are eliminated, but productiveness and general vigor are also 

 lost. Crossing restores immediately what is lacking in this respect. If the hybrid individ- 

 uals are self bred or bred among themselves, a rapid reduction in growth takes place which 

 if persisted in will take the plants back to the level of the inbred parents which were used 

 to make the cross. Hybrid vigor, therefore, is transitory in its effect and for the most part 

 incapable of fixation; it results from a temporary securing of all or many of the good qualities 

 from two diverse parents, since character factors, according to Bateson and Morgan, are 

 carried in groups, and it is these groups of hereditary potentialities which Mendelize. — 

 Chas. H. Otis. 



621. Jorger, J. Die Familie Markus. [The Markus family.] Zeitschr. Ges. Neur. u. 

 Psychol. 43: 76. 1918. 



622. Kajanus, Birger. Kreuzungsstudien an Winterweizen. [Studies on crossing win- 

 ter wheat.] Bot. Notiser 1918: 235-244. 1918.— Preliminary paper on genetic studies in 22 

 wheat crosses of pure lines from 17 different types. These types represent dicoccum, spelta, 

 tar gidum, and vulgar e. Studies have been made through from 2 to 5 generations, and have 

 included length of internode, awns, pubescence, color of glumes, number and color of kernels, 

 inner condition of si raw, and color of leaf auricles. The segregation of these characters in the 

 various crosses is briefly described. Crossings between vulgarc and dicoccvm gave in the F s 

 loose forms as in spelt. This spell form reached constancy in the ]•',, and when crossed with 

 vulgare showed dominance of the spell chan Crossings between vulgare and turgidum 

 gave in F 2 , close spelt-like forms, and in some cases spikelets with more than one kernel as 

 in vulgare and turgidum; one such constant form was crossed with vulgare and showed recessive- 

 ness of the spell characters. In all crossings with dicoccvm, spelta, and turgidum, squarehead 



