ANIMAL, PEODUCTION". 673 



sion (spurious allelomorphism). Further work showed that there had been 

 a repulsion in one case between the same two factors which had been coupled 

 in another case. The authors come to the conclusion that if A, a, and B, b, are 

 two allelomorphic pairs subject to coupling and repulsion the factors A and B 

 repel each other in the gametogenesis of the double heterozygote resulting from 

 the union Ab X aB, but will be coupled in the gametogenesis of the double 

 heterozygote resulting from the union AB X ab. The Fi heterozygote is osten- 

 sibly identical in the two cases, but its offspring reveals the distinction. The 

 possible significance of coupling and repulsion for breeding operations is 

 discussed. 



Under a given system in which a pair of factors are coupled it is possible 

 to produce repulsion by breeding together the rarer terms of the coupled 

 series, namely, Ab and aB. but the authors see no way to construct a coupling 

 system for the repelling system in the absence of a fresh variation. " This 

 consideration has an obvious application to those cases in which sex operates 

 as a repelling factor. In the fowl, the canary, and Abraxas grossulariata 

 femaleness thus acts as a repelling factor against various elements determining 

 pigmentation, and our experience of the plants leads us to suppose that if the 

 factors involved could be built up in the right combinations femaleness might 

 be coupled with the factors it now repels." 



" Extraordinary consequences, both to the distribution of the sexes, to the 

 distribution of factors between them, and perhaps to the causation of fertility, 

 must be anticipated If this condition could be fulfilled. There may be an In- 

 direct way of actually accomplishing these results. For, seeing that sex in the 

 fowl acts as a repeller of at least three other factors, when birds are built up 

 so as to be heterozygous for several of these, some of them may be found able 

 to take precedence of the others in such a way as to annul the present repul- 

 sions, with subsequent coupling as a consequence." 



An experiment in double mating', V. L. Kellogg (Science, n. ser,, 33 

 (1911), No. 855, pp. 183-189). — A discussion of apparent aberrations in double 

 mating of silkworm moths in work previously reported (E. S. R., 20, p. 1155). 



Double mating of silkworm moths, W. E. Castle (Science, n. ser., S.'f 

 (1911), No. 862, pp. 15-21). — Comments on the article noted above are given, 

 the view being expressed that double mating has produced nothing at variance 

 with the results of single mating, but that the work under discussion demon- 

 strates variance in dominance in common with results obtained by Couatgne 

 and Toyama. 



Measures for the protection and development of the national production 

 of live stock (Internat. last. Agr. [Rome], Bui. Bur. Econ. and Soc. Intel., 2 

 (1911), No. 5, pp. 265-273). — This contains statistical data and other infor- 

 mation on the live-stock industry in Italy, and proposes federal measures for its 

 promotion. 



Economic importance of live-stock production, H. W. Mumford (Atner. 

 Breeders Mag., 2 (1911), No. 1, pp. J{6-52, figs. 3). — This contains statistics on 

 the world's supply of live stock, and the importance of increasing the live-stock 

 production of this countiy is pointed out. 



On the botanical and chemical composition of different varieties of hay, 

 B. Tacke (Fuhling's Landw. Ztg., 59 (1910), No. 11, pp. 361-374; ahs. in ZentU. 

 Agr. Chem., 40 (1911), No. 3, pp. 192-197). — Chemical analyses are reported of 

 samples of hay which were gathered from different places, the chief object being 

 to compare marsh hay with that grown on the moors. The species of grasses 

 composing the principal part of each sample of hay are enumerated. 



Special feeding stuff analyses, 1911, R. E. Rose and E. P. Greene (Fla. 

 Quart. Bui., Dept. Agr., 21 (1911), No. 3, pp. i02-i 09). —Analyses are reported 



12544°— No. 7—11 6 



