20 HORTICULTURAL SOCIETY OF NLW 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 zvliite. 



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 n'hite and Delila x ivhite 

 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-j-W' X F-f D 



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

 the case, and all the hybrids are 



W-^W'+F-fD. 

 or F-fD 



or Dark red. 



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

 the formula : 



(F+W)" (D+W') = 

 or (F-f2FW+W) (D+2DW'-fW') 



which gives : 

 FD-fFW'-fDW-fWW'+2FDW'4-2FWW'+2DWW'+2FDW+4FWDW'. 



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

 FD+F+D+W-K2FD-f 2F +2D+2FD+4FD or, 



9 FD= Dark-red — 56.25% 



3 F = Flesh-colored = 18.75% 

 3 D = Delila = 18.75 % 



I W = White = 6.25% 



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



