No. 2, Makch, 1921] 



GENETICS 133 



and that of another is indicated. Effect of selection over periods 1893-1899, 1900-1906, 1907- 

 1913 and effect of season are discussed.— Steers are shown to weigh about 10 per cent more than 

 heifers at the same age. About 77 per cent of steers' and 81 per cent of heifers' weight at 33 

 months old, is put on in the first 22 months. Steers have larger proportion of gut fat, head, 

 hide, carcase; heifers a larger proportion of suet fat, tongue, tripe, intestine. Increasing age 

 increases proportion of carcase, suet fat, gut fat; decreases proportion of tongue, head, heart, 

 tripe, hide.— Cross-breeding showed no increase in weight over the heavier parent, where two 

 heavy breeds are crossed, the Fi is usually heavier than the mean of the two parents; where 

 a heavy and light breed is crossed the Fi is not so heavy as the mean of the parents either 

 way the cross is made. Crossing tends to obliterate sexual differences. The general effect 

 of cross-breeding is not, as has often been stated, to increase the rate of maturity in weight. 

 Crosses give a slightly larger proportion of carcase, gut fat, tongue and heart than the pure 

 breeds. The pure-breds are heavier in hide, head and blood.— The coefficient of variation of 

 live weight ranged between 7.29 and 11.98. This coefficient decreased between 1893 and 

 1913. The coefficients of variation for steers 33 months old were, carcase 4.0; suet fat 20.4; 

 gut fat 24.7; tongue 10.4; head 6.3; heart 12.5; tripe 15.8; hide 10.1; blood 17.2; intestine 21.8; 

 unaccounted for 23.5. — John W. Gowen. 



891. Hansen, W. Die Pflanzenziichterische Buchfuhrung und Bewertung der Zucht- 

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

 Pflanzenzucht. 6: 119-138. 2 fig. Dec, 1918.— The methods followed at the plant-breeding 

 station of Eckendorf near Bielefeld, Germany, in the collection and recording of field data on 

 breeding-plats with field crops are described in this article. The several observations may be 

 grouped as follows: (a) pedigree work; (b) observations on growing plants, harvest data, and 

 plans of selection plats; (c) notes taken during selection work; (d) behavior of the characters 

 in the various strains and families; and (e) guide to working methods, diary of work per- 

 formed, meteorological data, and germination tests.— Numerous specimen observation and 

 breeding forms specially arranged for recording various data on the cereal grasses, legumes, 

 and fibers, are included. — H. M. Steece. 



892. H(arland), S. C. The new theory of the origin of Sea Island cotton. Agric. News 

 (Barbados) 19: 100-101. 1920.— "Facts suggest that Sea Island cotton originated from a nat- 

 ural cross between a glabrous, broad-leaved West Indian native, with botanical affinities to 

 G. brasiliense, and some variety of American Upland." Author crossed a West Indian native 

 cotton of this type with an American Upland and obtained an Fi which was morphologically 

 almost indistinguishable from Sea Island and had fine silky lint more than 40 mm. long. Sev- 

 eral Fa plants also resembled Sea Island. "Actual reconstruction of Sea Island cotton by 

 this means has not been accomplished" but West Indian native type comprises many dif- 

 ferent strains. "Synthesis of Sea Island cotton could probably only be effected as a result of 

 the segregation of some rare gametic combination." — T. H. Kearney. 



893. Harrison, J. W. Heslop. A preliminary study of the effects of administering ethyl 

 alcohol to the lepidopterous insect Selenia bilunaria, with particular reference to the offspring. 

 Jour. Genetics 9: 39-52. Dec, 1919.— High mortality resulted from raising this insect, from 

 egg to adult, in alcohol fumes. The one male and four females that survived this treatment 

 were crossed with controls. Offspring from these crosses (100 eggs used) were "greatly 

 superior in several respects" to the controls; namely, in regard to viability of the eggs and 

 larvae, rate of development, pupal weight, and vigor (shown by pigmentation). In spite of 

 the small numbers, the author feels certain that these results are real, more especially since 

 Pearl's work with fowls seems to offer support. Pearl's hypothesis of the selective effect 

 of the alcohol treatment is explained at length.— £^. C. MacDowell. 



894. Harrison, J. W. Heslop. The inheritance of melanism in the genus Tephrosia 

 fEctropis) with some consideration of the inconstancy of unit characters under crossing. 

 Jour. Genetics 10: 61-86. S fig. July, 1920.— In crosses within limits of species T. crepuscu- 

 laria, inheritance of melanism proceeds on ordinary Mendelian lines. On the contrary, in 



