Origin of Species Variorum

slight variations or individual differences necessarily appear at an equally early period. We have little evidence on this head, but what we have certainly points the other way; for it is notorious that breeders of cattle, horses, and various fancy animals, cannot positively tell, until some time after birth, what the merits or form of their young animals will turn out. We see this plainly in our own children; we cannot .. tell whether a child will be tall or short, or what its precise features will be. The question is not, at what period of life each variation may have been caused, but at what period the effects are displayed. The cause may have acted, and I believe generally has acted, on one or both parents before reproduction. ↑ It deserves notice that it is of no importance to a very young animal, as long as it remains in its mothers womb or in the egg, or as long as it is nourished and protected by its parent, whether most ... of its characters are .. acquired a little earlier or later in life. It would not signify, for instance, to a bird which obtained its food .. by having a much-curved beak, whether or not whilst young it possessed a beak of this shape, as long as it was fed by its parents. ↑

I have stated in the first chapter, that ... at whatever age a variation first appears in the parent, it tends to reappear at a corresponding age in the offspring. Certain variations can only appear at corresponding ages; for instance, peculiarities in the caterpillar, cocoon, or imago states of the silk-moth: or, again, in the full-grown horns of cattle. But variations, which, for all that we can see might have appeared either earlier or later in life, likewise tend to appear at a corresponding age in the offspring and parent. I am far from meaning that this is invariably the case; and I could give several exceptional cases of variations (taking the word in the largest sense) which have supervened at an earlier age in the child than in the