POULTRY NOTES — 1909. IO5 



nian and Mendelian theory rests on a very, very slight founda- 

 tion of objective evidence in the first place, and in the second 

 place has an exceeding-ly pernicious tendency to obscure or 

 belittle the importance of the fact that inheritance is primarily 

 and fundamentally a physiological process. In regard to this 

 matter we are in entire accord with the general viewpoint re- 

 specting development and inheritance recently so distinctly and 

 forcibly set forth by Lillie* and Riddle.** 



The hypothesis here developed is made for strictly utilitarian 

 purposes, and zvithout any theoretical implication luhatever as to 

 the mechanism by zvhich the results symbolized are physiologi- 

 cally brought about. Indeed these "gametic" formulae are 

 looked upon by the writers as simply formulas of symbolic logic. 

 They lead to certain expectations for each generation. Are 

 these expectations fulfilled? If so, the formulas have served 

 the highly useful and scientific purpose of having predicted the 

 future course of natural events, and may be used in the future 

 to do the same thing again. If they are successful in these 

 predictions there must exist a biological reason why this is so. 

 To determine this reason is a problem for experimental inves- 

 tigation. 



Let us consider the three characters (a) barred color pattern, 

 (b) sex and (c) winter laying capacity, denoting the condition 

 of the organism with reference to these characters by the fol- 

 lowing scheme. 

 B = barred color pattern pres- b = barred pattern absent, i. e., 



ent. a non-barred bird. 



F = female sex. / = male sex. 



L, = Good winter egg produc- / = very poor winter egg pro- 

 tion. duction. 



Then assume that the breeds crossed in these experiments are 

 constituted as follows with reference to these three characters. 

 BfL . BfL = Barred Rock J' — a barred bird carrying good lay- 

 ing qualities, homozygous with 

 reference to all three charac- 

 ters. 



*Lillie, F. R. The Theory of Individual Development. Pop. Sci. 

 Monthly. Sept. 1909, pp. 239-252. 



**Riddle, O. Our Knowledge of Malanin Color Formation and its 

 Bearing on the Mendelian Description of Heredity. Biol. Bulletin. Vol. 

 XVI, pp. 316-351, 1909. 



