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THE AMERICAN NATURALIST [Vol. LI 



From the results as given it can be seen that the plants 

 with the combinations of habit of vine and shape of fruit 

 obtained in which duplicated the parental combina- 

 tions, are more numerous than expected, whereas the two 

 new combinations, with respect to these two factors, are 

 less than expected. The writers observed these facts and 

 commented upon them as follows : 



The percentage of plants which fall into each class are, however, 

 quite different from those of Mendel. This is of importance in that it 

 indicates the number of plants which it is necessary to grow in order to 

 get a plant with a certain combination of characters. Theoretically, 

 64 plants should have included all the combinations we secured; actu- 

 ally, with 452 plants there is one combination with only one representa- 



Our results would indicate that it is necessary to raise seven times as 

 many tomatoes as are theoretically necessary in order to secure a desired 



tendency seems to he for the second generation hybrids to go hack to the 



true for the yellow pear. Inertia seems to be a factor and the preserva- 

 tion of the status quo an object among tomatoes as among men (p. 23). 



In the light of more recent investigations of factorial 

 linkage it is recognized at once that the above statement 

 fulfils the conditions of linkage between at least two of the 

 allelomorphic pairs concerned. Let us then examine the 

 data more closely to see if a clear case of linkage can be 

 made out. 



Since the deviations above and below the expectancies 

 are about the same in both the red-fruited and yellow- 

 fruited plants, it indicates that color of fruit is an inde- 

 pendent factor and that habit of vine and shape of fruit 

 are partially linked with frequent breaks in the linkage. 

 Combining the figures for yellow and red fruit and putting 

 the 452 plants into 6 categories instead of 12, the 

 densed results given in Table II are obtained. 



1 The italics are mine. 



