20 HORTICULTURAL SOCIETY OF NEW YORK. 



169 flowering children of this specimen, and found the following figures for 

 the four principal types : 



Dark-red 58% 



Flesh-colored 17% 



Delila 20% 



White 4% 



These figures evidently indicate the same law of division as the first series, 

 but are to be assumed as a more careful representation, inasmuch as they are 

 gained from a greater number of individuals (169 instead of 49). 



The explanation of these figures is to be derived from Mendel's laws 

 for hybrids* under the assumption of the compound character of the original 

 color. On this assumption we have two pairs of antagonistic characters, viz. : 

 Flesh-colored and white. 

 Delila and white. 



The white is evidently to be taken as the absence of both of the two 

 opposite colors. It is not very easy to realize this condition, but yet it is clear 

 that the white may be nothing but the absence of any color. It is a negative 

 character, and is, if I may be allowed the comparison, simply the negation of 

 color. But now if the color is composed of two elements, only the negative 

 of both can lead to the white. Continuing this reasoning, I find that if we 

 take away from the original dark-red the flesh-color character, there will 

 remain the Delila, and if we remove the Delila the flesh-color will remain. 

 The white as the negative of the other component will be concealed in most 

 cases by the remaining positive character. 



From this reasoning we are justified to regard the crossing of red x white 

 as a di-hybrid crossing consisting of 



Flesh-colored x white and Delila x white 

 or F x W and D x W 



and in this way we come to a proposition equal to that worked out by MENDEL 

 for his crossings with two different pairs of antagonistic characters. 

 My original crossing is therefore to be represented by 



White X Red 

 or W+W' X F+D 



In the first generation the negative character is recessive, as is ordinarily 

 the case, and all the hybrids are 



W-fW'+F+D. 



or F+D 



or Dark red. 



In the following generation these dark red hybrids split up according to 

 the formula : 



(F+W) 2 (D+W') 2 



or (F+2FW+W) (D+2DW+W) 



which gives : 

 FD-fFW'+DW+WW'-f-2FDW'-f2FWW'-f2DWW'-f2FDW+4FWDW'. 



Now if W and W' are only the negatives of F and D, the positive result is : 

 FD+F+D+W+2FD+2F+2D+2FD+4FD or, 



9 FD Dark-red 56.25% 

 3 F = Flesh-colored = 18.75% 

 3 D = Delila = 18.75% 



! w = White = 6.25% 



*Ber. d. deut. bot. Ges. 18:83. 1900. 



