96 THE INFLUENCE OF HYBKIDITY. 



henceforth know that there is no basis in this universality of 

 reproduction for a serious argument, since we know that two 

 distinct species, two genera, in fact, can produce cross-breeds. 

 This faculty of reproduction has had too much importance 

 given to it, it is only a function, that is to say, a physiolo- 

 gical character quite improper for classification ; the existence 

 of bigenerate hybrids shows this sufficiently. It is a bad cha- 

 racteristic, because it is not a constant one ; because either 

 the man or the animal does not bear it in him, and that a 

 given uniformity of circumstances is necessary in order to 

 reveal this characteristic to an observer. It is the same with 

 animal forms, which do not countenance in any manner such an 

 observation; it is sufficient to recall the alternating genera- 

 tions of the invertebrata. Where shall we place all these aga- 

 mous animals ? how shall we class these proscolex and scolex, 

 which have no sex, and which will never have one ? Instead 

 of the idea of fecundity, which is insufficient to characterise a 

 species, we must substitute another, that of the development 

 of the produce. If everything shows us that zoosperms, pro- 

 ceeding from very different animals, can equally fecundate any 

 given ovum, if we even admit that we have no good reason 

 for rejecting the theory that each ovum can be impregnated by 

 different kinds of zoosperms, it is very easy, on the contrary, 

 to account for the fact that offspring will have no chance of 

 life, except so far as the two parents show a sufficient identity, 

 but which we cannot regard as fit to characterise species. 



As the produce of two organisms, a descendant ought always 

 to be considered as the result of two united halves fitted 

 together, and combined one with the other. If the two halves 

 are identical, the animal is like its progenitors in everything. 

 If the two beings, who have endeavoured to unite themselves, 

 are too dissimilar, the two forces cannot combine, and there is 

 either no produce, or it is arrested in its development from the 

 first moment of its embryo life. If the two forces, or the sum 

 of the two forces, have a certain amount of common direction, 

 they can produce a new being, but an imperfect one, and 

 which will not have all the conditions of existence like its 

 parents ; it will not have genital power, and consequently will 



