Page:Mendel's principles of heredity; a defence.pdf/83

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63

This experiment was made in precisely the same way as the previous one. Among all the experiments it demanded the most time and trouble. From 24 hybrids 687 seeds were obtained in all these were all either spotted, grey-brown or grey-green, round or angular[1]. From these in the following year 639 plants fruited, and, as further investigation showed, there were among them:

 8 plants ABC. 22 plants ABCc. 45 plants ABbCc.
14 ABc. 17 AbCc. 36 aBbCc.
 9 AbC. 25 aBCc. 38 AaBCc.
11 Abc. 20 abCc. 40 AabCc.
 8 aBC. 15 ABbC. 49 AabbC.[errata 1]
10 aBc. 18 ABbc. 48 AaBbc.
10 abC. 19 aBbC.
 7 abc. 24 aBbc.
14 AaBC. 78 AaBbCc.
18 AaBc.
20 AabC.
16 Aabc.

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 78 times and is hybrid in all of the characters. The ratios 10, 19, 43, 78 agree so closely with the ratios 10, 20, 40, 80, or 1, 2, 4, 8, that this last undoubtedly represents the true value.

The development of the hybrids when the original

  1. Correction: AabbC. should be amended to AaBbC.: detail
  1. [Note that Mendel does not state the cotyledon-colour of the first crosses in this case; for as the coats were thick, it could not have been seen without opening or peeling the seeds.]