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to seven contrasted pairs of characters— 6'. g. the form of the ripe seeds, 

 whether round or angular (wrinkled), the colour of the cotyledons, 

 whether yellow or green, the length of the stem, whether long or 

 short, and so on. Specimens of each pair were united by cross- 

 fertilisation, and in every case the resulting hybrids were of one type 

 only, so far as each pair of characters was concerned. The 

 character which thus appeared to the exclusion of the other was 

 termed by Mendel the " dominant " character, and the one which 

 was suppressed he called the " recessive " character, because he 

 found by his subsequent work that it had not been destroyed, but 

 had only receded from view owing to the overpowering influence of 

 the dominant character. 



When the hybrid peas thus produced were reared and self-fertilised 

 Mendel found that they gave rise to progeny (as shown by subsequent 

 plantings) consisting of individuals of three kinds in approximately 

 the following proportions, viz. one containing the dominant character 

 only, one containing the recessive character only, and two containing 

 both the dominant and recessive characters, but with the appearance 

 of pure dominants. In outward appearance, therefore, the genera- 

 tion raised from the hybrids was in the proportion of three dominants 

 to one recessive, and this was found to be true whenever hybrids 

 were self-fertilised or crossed inter se. Some of the actual figures 

 obtained were as follows : Round seeds 5474, angular seeds 1850, 

 yellow cotyledons 6022, green cotyledons 2001. 



Mendel also found that when two pairs of characters (say round 

 and angular seeds, yellow and green cotyledons) were considered 

 together, four forms differing in outward appearance were obtained, 

 and in such proportions as might have been calculated from the 

 ratio already obtained for a single pair, viz., 9 ry + 3 rg 4- 3 ay + 

 1 ag, which equals (3 r -f 1 a) x (3 y + 1 g). It is important to 

 note that two of the four forms, namely, the rg's and the ay's, 

 were new combinations, and also that in each of the four groups 

 one individual was found to be pure with respect to the characters it 

 exhibited, while the others were more or less hybrids. A corre- 

 sponding result was obtained when three pairs of characters were 

 simultaneously watched, and good evidence was obtained that all 

 seven pairs of characters dealt with were in like manner inde- 

 pendent of one another. 



These important results were explained by Mendel in a very 

 simple but nevertheless very ingenious manner. He argued that, 

 as in ordinary experience, pure races can only be maintained 

 by the mating of individuals showing the same characteristics, so 

 when a pure stock emerges from hybrid parents (as his experiments 

 had shown to be possible) it must be due to the mating of germ-cells 

 which contained the factors for one character only of each pair and 

 not the other. He assumed, therefore, that in the formation of the 

 germ-cells of hybrids, whether male or female, a separation of the 

 determining factors for the different characters takes place in such a 



