189C.] 181 [Ortmann. 



average fitted for the particular conditions of life, or another direction of 

 orthogenesis prevails among the surviving individuals of each group, and 

 after ^permanent separation during a series of generations the changes in 

 each separated group amount to what is called specific diflTerences. 



If we compare in this respect the origin of species in nature with the 

 art of the breeder, we see at once that separation is implied in the action 

 of man. The breeder not only selects his material— in so far he complies 

 with the requirement of natural selection— but he isolates it from the 

 other individuals, and farther on, his chief occupation is the repeated 

 application of the same principle in the separated stock of animals and 

 their descendants, namely, the selection only of individuals answering 

 his wishes. This action corresponds exactly to natural selection in 

 isolated localities. Thus the breeder clearly unites two difi'erent actions. 

 (1) The selection of particular individuals possessing certain desired 

 characters corresponds to natural selection. But the breeder cannot, or 

 cannot completely, destroy the rejected remainder. (3) Accordingly he 

 directs his chief attention to the isolation of the selected material, in order 

 to secure control over the true breeding in subsequent generations. Since 

 the organisms kept under domestication are mostly amphimixotic,* the 

 breeder must exclude especially the possibility of interbreeding with the 

 outsiders. This latter point, although clearly understood by Darwinf 

 himself, has been overlooked generally. It was forgotten, that beside the 

 material used for breeding, there exists other " raw " material, and that 

 the preservation of the latter constitutes a very important difference from 



* As regards the origin of races as well as of species it matters nothing, whether the 

 respective organism is amphimixoiic or not (see Grundziige, etc., p. 32). Amphimixis, 

 tliat is to pay propagation by crossing effects equality, the fusion of dififerent characters, 

 and not, as Weisraann asserts, the appearauee of new variations. This law is not only 

 logically evideut, but is amply demonstrated by facts. Comp. Darwin, Variation of Ani- 

 mals and Plants under Domestication, 2d ed., ii, 1S76, p. 62ff., where numerous examples of 

 the equalizing power of crossing are recorded. This question is to be looked upon as 

 finally settled already by Darwin and no doubt in the most convincing manner, namely, 

 by well-established facts. It is extremely unintelligible how Weismann could throw 

 oside all the proofs carefully collected by Darwin and substitute his own ill-founded con- 

 ception of Amphimixis. I may add here that between the action of Amphimixis and 

 that of Panmixia as accepted by Weismann, there exists a grave logical error. Amphi- 

 mixis is the simple process of crossing occurring but once, Panmixia is the same process 

 repeated often and in difTerent directions : the effects of both can only differ in quantity. 

 According to Weismann, however, Amphimix of different animals results in new differ- 

 ences, Panmixia of different animals in the disappearance of existing differences (vari- 

 ations without value for selection are absorbed). This remains an insurmountable con- 

 tradiction until Weismann demonstrates that his Amphimixis and Panmixia are concep- 

 tions contradictory to each other. Eimer {Eatstehung der Arten, i, 1888, p. 48) says. 

 Amphimixis may produce new things by uniting different things. That is true in so far 

 as the offspring is different from either parent. But this is the first step in uniting the 

 characters of the parents. The single individuals resulting from the same or similar cross- 

 ings are more alike to each other than the parents were to each other. 



t Darwin ( Variation under Domestic, ii, p. 62) says : " The prevention of free crossing, 

 and the intentional matching of individual animals, are the cornerstones of the 

 breeder's art," and "Xo man in his senses would expect to improve or modify a breed 



. . . unkss he separated his animals." 



