No. 2, September, 1920] GENETICS L95 



when panicles shoot, the bag is immediately suspended over each panicle and tied around its 

 stem so that it is protected from undesirable pollen before any florets open. Cane blossom 

 is hermaphrodite but some varieties are almost completely self-sterile, making it possible to 

 cross-pollinate with another variety with assurance that nearly all offspring will be hybrids 

 of the two chosen varieties. Pollinating is done by placing panicles of desired variety in bag, 

 in Buch position that pollen will be shed or carried by wind or insects to florets of other variety 

 as they open. One or two panicles are used at a time, allowed to remain in bag two or three 

 days, being renewed as often as necessary. It is found advantageous to cut stems 4 to 6 

 feet long and put cut end in joint of bamboo filled with water, thus keeping fresh 2 or 3 days. 

 — Results: 1915-1910. Ten crosses attempted, eight produced seedlings, majority of which 

 showed characteristics of both parents. About 1500 seedlings produced, one panicle yielding 

 over 1000.— 1916-1917. Thirty crosses made comprising nine different combinations, of which 

 nineteen were successful. From one combination 1309 seedlings were obtained and in all 

 2589 were produced. — 1917-1918. Thirty crosses were attempted, comprising nine combina- 

 tions. Fifteen were successful and 1794 seedlings were produced, 157 from one combination, 

 735 from another. — Effect of crossing: In 1915-1916 and 1916 1917 pollinator was dark-colored 

 cane while seed-parent was medium light, and dark color of pollen parent was seen in many 

 of offspring. — At least two of old standard varieties are nearly pollen-sterile here (Crystalline 

 and Rayada).— #. E. Barker. 



1479. Cunningham, J. T. Results of a Mendelian experiment on fowls, including the pro- 

 duction of a pile breed. Proc. Zool. Soc. London 1919: 173-202. 1 pi. Sept., 1919.— A male 

 black-red Gallus bankiva was crossed to a silky hen. Data on inheritance of plumage, skin 

 pigmentation, comb, booting and crest are given. The production of a pile race from the 

 cross, which bred true, is described. "The simplest explanation" of its origin "is that seg- 

 regation is not complete or perfect . . . ." Attempts to increase amount of pigmenta- 

 tion in the piles by repeated back-mating to normals did not result in any consistent increase. 

 — H. D. Goodale. 



1480. Danforth, C. H. Resemblance and difference in twins. Jour. Heredity 10: 399- 

 409. Frontispiece, fig. 1-14, 20, 22-30. Dec, 1919. 



1481. Daniel, L., and H. Tetjlie. Extension des limites de culture de la vigne au moyen 

 de certains hybrids. [Extension of the limits of culture of the grape by means of certain 

 hybrids.] Compt. Rend. Acad. Sci. Paris 166: 297-299. 191S. 



1482. Davenport, C. B. A strain producing multiple births. Jour. Heredity 10: 382- 

 384. Nov., 1919. 



1483. Delage, Y., and M. Goldsmith. Le Mendelisme et le mecanisme cytologique de 

 l'heredite. [Mendelism and the cytological mechanism of heredity.] Rev. Sci. Paris 57: 

 97-109, 130-135. 1919.— Part I is a brief summary of Mendelism, "Neo-Mendelism" and the 

 chromosome theory of heredity, including the factorial hypothesis, the phenomena of linkage, 

 crossing over and non-disjunction and the chromosomal mechanism of sex determination. 

 Mendelism is compared withWeismannism. Credit Natjdin with many discoveries attributed 

 to Mendel. Mention influence of environment and cytoplasmic inheritance. Part II is a 

 critique of Mendelism (or Neo-Mendelism). Acknowledge great advances and brilliant 

 achievements in this field but think Mendelians are blinded to the uncertainties, defects, 

 lacunae and improbabilities of the theory and the fragility of the objective bases upon which 

 it rests. Illustrate (1) by questioning continuity of chromosomes because these are not 

 visible in resting stage, (2) by questioning linear arrangement of genes because chemical 

 differentiation of chromatin within individual chromosomes has not been demonstrated, (3) 

 by contending that a force which will bring homologous chromosomes into such intimate and 

 accurate alignment as necessitated by crossover hypothesis will not permit them to lie X-wise 

 and give crossovers, and (4) by maintaining that Mendelian conception gives no explanation 

 of successive appearance of characters in ontogeny or, (5) of the origin of new character- 

 during evolution. Predict downfall of Mendelism from weight of accessory hypotheses neede> I 

 to explain special cases. — C. 11'. Metz. 



