354 MendeVs Experiments 



The whole expression contains 27 terms. Of these 8 

 are constant in all characters, and each appears on the 

 average 10 times; 12 are constant in two characters, and 

 hybrid in the third ; each appears on the average 19 times ; 

 6 are constant in one character and hybrid in the other 

 two ; each appears on the average 43 times. One form 

 appears "]% times and is hybrid in all of the characters. 

 The ratios 10, lig, 43, 78 agree so closely with the ratios 

 10, 20, 40, 80, or I, 2, 4, 8, that this last undoubtedly 

 represents the true value. 



The development of the hybrids when the original 

 parents differ in three characters results therefore according 

 to the following expression : 



ABC + ABc + AbC + Abe + aBC + aBc + abC + abc + 

 2 ABCc + 2 AbCc + 2 aBCcAr 2 abCc-^2 ABbC+ 2 ABbcA- 

 2 aBbC + 2 aBbc + 2 AaBC + 2 AaBc + 2 AabC-h 2 A abc + 

 4 ABbCc + 4 ^^^CV + 4 AaBCc + 4 AabCc + 4 AaBbC + 

 4 ^^^^^ + 8 AaBbCc. 



Here also is involved a combination series in which the 

 expressions for the characters A and ^, j5 and by C and ^, 

 are united. The expressions 



A + 2Aa-\-a 

 B'\-2Bb + b 

 C + 2CC + C 



give all the classes of the series. The constant combinations 

 which occur therein agree with all combinations which are 

 possible between the characters A, B,C, a, b^ c\ two thereof, 

 ABC and abc, resemble the two original parental stocks. 



In addition, further experiments were made with a 

 smaller number of experimental plants in which the re- 

 maining characters by twos and threes were united as 

 hybrids : all yielded approximately the same results. There 

 is therefore no doubt that for the whole of the characters 

 involved in the experiments the principle applies that the 

 offspring of the hybrids in which several essentially diffej'ent 

 characters are combined exhibit the terms of a series of 

 combinations, in which the developmental series for each pair 

 of differentiating cha^^acters are united. It is demon- 

 strated at the same time that the relation of each pair of 



