ZXll GENERAL INTEODDCTION. 



ing, suggestions of some of their ancestors. The offspring 

 of two individuals (unless very closely related) differ m 

 much the same way, only the possibilities for variation 

 are infinitely greater. The raw material, the living clay 

 or protoplasm, out of which the new individual is de- 

 veloped, comes, as it were, from different qua-rries, with in 

 each case a different historj\ In the struggle amongst 

 the parts, as the development proceeds the legionaries of 

 the immediate ancestors are sometimes worsted by those 

 of the less recent ancestors, the grandparents being vic- 

 torious in the centre, while still more remote ancestors 

 secure occasional successes in the wings. The final result 

 is in most cases a drawn battle, neither particuLirly satis- 

 factory to those immediately concerned, nor to the world 

 at large. 



According to Mr. Galton's law of ancestral heredity, 

 the two parents contribute half, the four grandparents 

 one fourth, the eight great-grandparents one eighth, and 

 so on, of the total heritage of the average offspring. It 

 is, however, conceivable that, owing to what, for want 

 of a better name, may be called antagonism between 

 the protoplasmic units during fertilisation and develop- 

 ment, the grandparents, or even the great-grandparents, 

 might contribute more than the immediate parents, and 

 that, vvflien the " antagonism " is still more pronounced, 

 the comparatively remote ancestors might become the 

 main contributors. Darwin was the first to point out 

 that the offspring of parents belonging to different 

 species, or distinct varieties, do not, as might have been 

 expected, occupy an intermediate position, but take after 

 a remote ancestor. Now-a-days the possibility of rever- 

 sion is sometimes called in question. I have never- 

 theless endeavoured to account for my hybrids differing 

 in their markings from tlieir sire by the reversion hypo- 

 thesis, and I have made a number of experiments with 

 the object of testing the probability of this explanation. 

 Some of these experiments I shall now mention. 



(1) Pigeons. — With the numerous varieties of pigeons a 

 countless number of experiments have been made by 



