238 • THE ORCHID REVIEW. 



He found that when peas having yellow and green cotyledons were crossed, 

 the yellow colour was dominant and the green ivn s>i\e, and when the hybrids 

 were self-fertilised the resulting seeds were either yellow or green, but tM 

 former were three times as numerous as the latter. New fertilisation con- 

 sists of the union of two cells of opposite sexes (called -imet.-s before con- 

 jugation), and the gamete of either sex is equally c ipabie of transmitting a 

 character. If therefore a male and female gamete of the pure yellow character 

 united the offspring would be yellow, and if green with gre'en the offspring 

 would be green. But if a yellow male gamete united with a green female, 

 and a green male with a yellow female, the result in both cases, under the 

 Law of Dominance, would be a yellow seed (yellow being dominant, and 

 green recessive), hence the proportions of three yellow seeds to one 

 green. The union of unlike gametes (green with yellow) alone yielded 

 hybrids (those of like gametes reverting to the pure parental character*, and 

 these again self-fertilised repeated the process in the same proportions, 

 yellow with green alone remaining hybrid, the rest reverting ; and so on to 

 subsequent generations. But the same plant may at the same time exhibit 

 dominant and recessive characters in opposite pairs of several other kinds, 

 hence there is a degree of complexity which can hardly be followed up by 

 experiment, the results becoming unmanageable. 



Weldon, however, argues that the flaw in Mendel's woik consists in 

 neglect of the ancestry of the races with which he worked, and the tendency 

 to regard this offspring as resembling their individual parents instead of 

 the race to which they belong, and shows that races having a different 

 ancestry behave differently. He also shows a scale of intermediates in 

 (i) colour, and (2) shape, (another character which Mendel dealt with). 

 By the way, it is curious that Mendel had no intermediates, but he seems 

 to have sorted everything into either yellow or green, though he admits 

 having at first sorted some into the wrong division. Weldon also argues 

 that Alternative Inheritance alone may produce something like Mendel's 

 Law of Segregation, but not comparable with his Law of Dominance. 



The conceptions of "unit-characters," put forward to explain the 

 numerical proportions in which the dominant and recessive characters are 

 said to appear in successive generations, is certainly ingenious, and recalls 

 the one put forward to account for the supposed fact that acquired 

 characters— those which first appear in the lifetime of the individual 

 because of the environment— are never reproduced. The theory is that 

 there is a germ-plasm, from which new individuals are produced, which is 

 unaffected by the environment, and consequently remains pure. But if 

 acquired characters were never transmitted— if every individual reproduced 

 itself absolutely pure and uncontaminated— no evolution would be possible. 

 There is now a sort of modification of the theory, that if the effect of the 



