90 Vererbung, Variation, Mutation. 



croire absolument identiques, donnent des resultats fort differents suivant les 

 cas et les annees, ce qui doit mettre l'experimentateur en garde contre des gene- 

 ralisations prematurees. Gatin. 



221) Harris, J.A., On dil'f erential mortality with respect to seed weight 

 occurring in field cultures of Pisum sativum. In: Amer. Natural., Bd. 48, 

 Heft 2, S. 83—86, 1914. 



In previous papers the author shows that in the dwarf varieties of beans 

 there is selective mortality of the seeds. In the present paper dwarf peas were 

 studied in the same way. It appears that in seven of the ten series the varia- 

 bility of the seeds which survived is less than that of those which failed. The 

 inrmediate physical or chemical cause of this selective death rate is at present 

 unknown. Gates. 



222) Bailey, P. G., Primary and Secondary Reduplication Series. In: 

 Journ. of Genetics, Bd. 3, Nr. 3, S. 221—227. 1914. 



The author discusses the phenomena of 'gametic coupling' in Sweet-peas in 

 connexion with Trow's hypothesis of primary and secondary reduplication. 

 When three pairs of 'coupled' characters are concerned together, the results may 

 be explained either on the hypothesis that the coupling affects all three pairs of 

 factors, or that it affects only two, and that the apparent coupling between the 

 third pair is due simply to their coupling with the others. The author examines 

 the numerical results that would arise on each hypothesis, and concludes that the 

 second on the whole fits the observed results better than the first. In any case 

 it is clear that the ratio of coupling between a pair of factors is different when 

 they are associated with other coupled factors than when they alone are con- 

 cerned. Doncaster. 



223) Price, H. L., Inheritance in Cabbage Hybrids. In: Annual Rept. 

 Va. Polytech. Inst, Agr. Exp. Sta., S. 240—257, 1911 — 1912. 



Numerous crosses among cabbages were made, involving the following set 

 of differentiating attributes: blistered and smooth leaf, head and headless cab- 

 bage, cabbage and cauliflower type of head, cauliflower and headless cabbage, 

 terminal and axillary (head) growth, kohlrabi and head cabbage. 



"In all of these crosses the resultant hybrid considered as a whole presented 

 the appearance of a blend, but when the major differentiating characters alone 

 were considered it was seen that one character usually dominated the other 

 although the dominance could not be called absolute or complete in all cases. 

 In the case of Brüssels sprouts crosses the result appears to be a mosaic, but 

 this is presumably due to the fact that there is no actual pairing between ter- 

 minal and axillary heads or buds, but that each is dominant to its absence. In 

 the second generation hybrids in all cases the hybrid type persists. Whether 

 we consider the first generations dominants, mosaics, or blends the second gene- 

 rations fail to show any sign of segregation. The following conclusions are 

 drawn : The inheritance in the first generation is preponderant if not completely 

 dominant. The lack of segregation in the F 2 hybrids indicates that the inheri- 

 tance for these characters in cabbage is not Mendelian but permanently preponde- 

 rant or exclusive." Pearl. 



224) Hayes, H. K., Variation in Tobacco. In: Journ. of Heredity, Vol. V, 

 Nr. 1, S. 40—46, 1914. 



This is a continuation of previous work. A study of the heredity of sepa- 



