386 MAINB AGRICUI.TURAI. e;xpe:riMENT STATION. I912. 



tally studied warrants. It must be recognized as possible, if not 

 indeed probable, that other races or breeds of poultry than those 

 used in the present experiments may show a somewhat different 

 scheme of inheritance of fecundity. The directions in which de- 

 viations from the plan here found to obtain may, at least a 

 priori, most probably be expected are two. These are : (a) 

 differences in different breeds in respect to the absolute fecun- 

 dity value or worth of the factors which determine the expres- 

 sion of this character, and {h) gametic schemes which differ 

 from those here found either in the direction of more or fewer 

 distinct factors being concerned in the determination of fecun- 

 dity, or in following a totally different type of germinal reac- 

 tions. 



Regarding the first point it will be recalled that in several 

 places in the body of the paper it has been suggested that the 

 absolute fecundity value (i.e., the degree of actual fecundity 

 determined by the presence of the gametic factor) may differ 

 for the factor Li in the case of the Barred Rock as compared 

 with the Cornish Indian Game breed. It is hoped later to take 

 up a detailed study of this point, on the basis of the material 

 here presented, and additional data now in process of collection. 

 Wherever there is a difference in the absolute fecundity value 

 of the Li factor, it means that the division point for the classifi- 

 cation of winter productions should be taken at a point to corres- 

 pond with the physiological facts. In this first study the division 

 at 30 eggs has been found to accord sufficiently well for practical 

 purposes with the actual facts. Similarly the absolute fecundity 

 value of the excess production factor L-. may be different in 

 different breeds. In applying the results of this paper to the 

 production statistics of other breeds of poultry the possibility of 

 differences of the kind here suggested must always be kept in 

 mind. 



The second point (the possibility of gametic schemes for fe- 

 cundity differing qualitatively from that found in the present 

 study) is one on which it is idle to speculate in advance of defi- 

 nite investigations. I wish only to emphasize that nothing is 

 further from my desire or intention than to assert before such 

 investigations have been made that the results of the present 

 study apply unmodified to all races of domestic poultry. 



