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THE AMERICAN NATURALIST [Vol. XLV 



Crossing short-eared and long-eared races, he gained 

 an F r generation with almost intermediate ears, and here 

 no segregation was observed in F 2 . 



But even this case may agree with Mendelian laws. 

 The idea for such interpreting is won — as Lang has 

 clearly pointed out — by means of Nilsson-Ehle 's (and 

 East's) experiments, the former concerning the colors of 

 wheat-grains, the latter dealing with the number of 

 1 1 rows ' ' in the ears of maize. Nilsson-Ehle demonstrated 

 that blending of red and white color in wheat is appa- 

 rently a fiction: The red color is determined by several 

 different genes, acting in the same sense and augmenting 

 the effect of each other. Hence by segregation and new 

 combinations of these approximately equipotent genes a 

 whole series of gradations in red color will be realized. 

 And these gradations must group themselves symmet- 

 rically around the phenotype of the F x in question. If 

 we have to consider say three genes, A, B and C, we shall 

 for F 1 use the formula AaBbCc, indicating the value 3 

 which is intermediate between aabbcc as zero and 

 AABBCC as 6. Even in case of no fluctuation such a 

 series must present itself as an almost continuous grada- 

 tion, and it is not difficult to find out that the progeny of 

 every " class" here will breed true, i. e., the average of 

 the progeny's character will be like the ' 1 class" of the 

 parent. 



Just so it is in the case of East's experiments with 

 maize, as East himself has clearly illustrated. Thus, 

 well-analyzed instances of heredity in plants, concerning 

 both color-factors and meristic factors may be compared 

 with Castle's case in question. Lang in his interesting 

 criticisms points out that certain irregularities in Castle's 

 Fjj-material give strong evidence for the view that we 

 have no blended inheritance but true segregation here as 

 well as in the cases of Nilsson-Ehle (and, as we may add, 

 in the cases of East). Further analysis may then prob- 

 ably demonstrate in a more direct manner the true nature 

 of the apparent blending in Castle's case ; as yet we can 



