246 GENETICS [Bot. Absts., Vol. VI, 



genes between pairs of homologous chromosomes, or (3), especially in the case of disease con- 

 ditions, to a tendency on the part of the germplasm to return by degressive mutations to the 

 normal and presumably more stable condition. — C. H. Danforth. 



1681. Hansen, W. Einiges u'ber Riibenzucht. [Something about beet-breeding.] Illustr. 

 Landw. Zeitg. 39: 154-156. 1919. — Author advocates permitting open-pollination among best 

 mother-beets and subsequent evaluation based on progeny performance. A single seed 

 obtained under a gauze bag gave a poor result as revealed by progeny test. Determination of 

 dry weights of beets in addition to polarization was deemed unnecessary. Suggests designat- 

 ing beet by letters in genetical studies. [From author's abstract in Zeitschr. Pflanzenzucht. 

 7: 120. Dec, 1919.]— J. P. Kelly. 



1682. Hansen, W. Die Pflanzenziichterische Buchfiihrung und Bewertung der Zucht- 

 pfianzen. [Plant-breeding book-keeping and evaluation of the parent plants.] Zeitschr. 

 Pflanzenzucht. 6: 119-138. 2 fig. Dec, 1918. 



1683. Hansen, W. Gedanken iiber Organisation und Arbeitsersparnis in der Pflanzen- 

 zucht. [Thoughts on organization and labor-saving in plant breeding.] Deutsch. Landw. 

 Presse 1918:261-262. 1918.— See Bot. Absts. 6, Entry 1587. 



1684. Hansen, W. Die Ermittlung des Einzelkorngewichtes einer Pflaaze. [Determi- 

 nation of the weight of individual grains of a plant. Zeitschr. Pflanzenzucht. 7 : 225-227. June, 

 1920. 



1685. Hargitt, George T. Coelenterates and the evolution of germ cells. Anat. Rec 

 17: 327. Jan., 1920. — Author's abstract of paper read before the American Society of Zoolo- 

 gists, St. Louis, December 30, 1919. — In the Hydrozoa the observations upon germ-cell origin 

 and segregation, budding, regeneration, and development from dissociated cells have led to 

 the following conclusions: All cells of the body (except possibly the nettling and nerve cells) 

 are capable of further differentiation in various directions; this includes the power of dedif- 

 ferentiation and of specialization in a new direction. There cannot be, therefore, any real 

 distinction between body cells and germ cells. — Specialized cells of other adult animals (in- 

 cluding vertebrates) show, in varying degrees, the power of dedifferentiation and new speciali- 

 zation. The capacity for specialization in different directions is universally present in the 

 cells of embryos or of larvae, and sometimes throughout the youthful stages. But there 

 is a time in ontogeny when further specialization of cells involves the loss of capacity for any 

 new differentiation; this is the period at which germ cells are usually segregated into a distinct 

 tissue. In the higher organisms this may occur early in ontogeny; in Hydrozoa it never 

 occurs. — George T. Hargitt. 



1686. Harland, S. C. Studies of inheritance in cotton. I. The inheritance of corolla 

 colour. West Indian Bull. 18: 13-19. 1920. — "It would easily be possible to collect a hundred 

 or more different pure-breeding West Indian natives." Existence of so large a number of 

 homozygous biotypes is attributed to long-continued isolation in gardens. Present paper 

 deals with artificial hybrids of some of the "native" cottons with Upland and with Sea Island. 

 — Author distinguishes 6 grades of color from white (grade 0) to very deep yellow (grade 5), 

 all breeding true. Ten different combinations were made among these. "A cross between 

 any two of the above shades gave an intermediate Fi. In all F2 families, the parental and Fi 

 color types appeared, but there may have been other intermediate colour forms in addition." 

 In F« of the most extreme cross (0 X 5) the distribution was: very deep j^ellow. 1 ; intermediate. 

 72; white, 4. An F 3 of this combination was not grown. The combination 0X3 gave in Fj 

 a ratio of 4.4 yellow : 1.0 white. In F 3 , 8 families from F 2 yellows produced yellows only, 

 and 27 families from F2 j'ellows produced yellows and whites in an approximately 3 : 1 rati". 

 but with considerable deviation from this ratio in certain families. Of 11 families from F2 

 whiles, 6 produced an occasional yellow in F ; , but possibility oi ' cross-pollination 

 as an explanation is not excluded. "If is not without hesitation that, the hypothesis that 

 n. ciliutn yellow and white constitute an allelomorphic pair is put forward."—? 7 . //. Kearrn 



