94: ON CERTAIN CHARACTERS NOT BLENDING. Chap. XV. 



been some mistake, if the plants which were at first identical with the 

 paternal variety, namely, the painted-lady, had not later in the season 

 produced, as mentioned in a former chapter, flowers blotched and streaked 

 with dark purple. I raised grandchildren and great-grandchildren from 

 these crossed plants, and they continued to resemble the painted-lady, but 

 during the later generations became rather more blotched with purple 

 yet none reverted completely to the original mother-plant, the purple 

 sweet-pea. The following case is slightly different, but still shows the 

 same principle: Naudin 20 raised numerous hybrids between the yellow 

 Linaria vulgaris and the purple L. purpurea, and during three successive 

 generations the colours kept distinct in different parts of the same flower. 



From such cases as the foregoing, in which the offspring of the first 

 generation perfectly resemble either parent, we come by a small step to those 

 cases in which differently coloured flowers borne on the same root resemble 

 both parents, and by another step to those in which the same flower or 

 fruit is striped or blotched with the two parental colours, or bears a single 

 stripe of the colour or other characteristic quality of one of the parent- 

 forms. "With hybrids and mongrels it frequently or even generally happens 

 that one part of the body resembles more or less closely one parent and 

 another part the other parent ; and here again some resistance to fusion, 

 or, what comes to the same thing, some mutual affinity between the organic 

 atoms of the same nature, apparently comes into play, for otherwise all parts 

 of the body would be equally intermediate in character. So again, when 

 the offspring of hybrids or mongrels, which are * themselves nearly inter- 

 mediate in character, revert either wholly or by segments to their ancestors, 

 the principle of the affinity of similar, or the repulsion of dissimilar atoms, 

 must come into action. To this principle, which seems to be extremely 

 general, we shall recur in the chapter on pangenesis. 



It is remarkable, as has been strongly insisted upon by Isidore Geoffroy 

 St. Hilaire in regard to animals, that the transmission of characters withou 

 fusion occurs most rarely when species are crossed ; I know of one excep- 

 tion alone, namely, with the hybrids naturally produced between the 

 common and hooded crow (Corvus corone and comix), which, however, 

 are closely allied species, differing in nothing except colour. Nor have I 

 met with any well- ascertained cases of transmission of this kind, even when 

 one form is strongly prepotent over another, when two races are crossed 

 which have been slowly formed by man's selection, and therefore resemble 

 to a certain extent natural species. Such cases as puppies in the same 

 litter closely resembling two distinct breeds, are probably due to super- 

 foetation,— that is, to the influence of two fathers. All the characters 

 above enumerated, which are transmitted in a perfect state to some of 

 the offspring and not to others, — such as distinct colours, nakedness of 

 skin, smoothness of leaves, absence of horns or tail, additional toes, pelo- 

 rism, dwarfed structure, &c, — have all been known to appear suddenly in 

 individual animals and plants. From this fact, and from the several slight, 

 aggregated differences which distinguish domestic races and species from 



t 



20 * Nouvelles Archives du Museum,' torn. i. p. 10 









