1896.] LoD [Ortmaun. 



But we do not need this at all. Halmatogenesis is a well-known process 

 of inheritance, and comes under different heads in that chapter. For 

 example, accumulative inheritance (even orthogenesis) may effect a 

 sudden rise of the degree of development of a certain character, or char- 

 acters remaining latent during one or more generations may come sud- 

 denly into reappearance, or farther, atavism may effect the same. Hal- 

 matogenesis does not at all play a part in the breaking up of a " chain of 

 organisms," but it takes part only in the formation of varieties. 



Therefore, of Eimer's new terms, only Oenepintasis and Kyesamecliania 

 may form different species, and both are nothing else than Separation, or 

 as Eimer himself says : "the interruption of connection." 



i3y this brief sketch of Eimer's views we see that there is no consider- 

 able difference from Darwin's theor3%* except that he considers natural 

 selection to be of minor importance. Tliis is probably due to the fact that 

 he has investigated chiefly characters not at all subject to natural selec- 

 tion. He forgets, however, that even upon animals provided with indif- 

 ferent characters natural selection must necessarily act in order to main- 

 lain the good standard of all the other characters. All the principles 

 introduced by Eimer : Orthogenesis and halmatogenesis as forming varie- 

 ties in a distinct direction, genepistasis and kyesamechania as forming 

 species, are onl}- new words for old ideas, which indeed have been set 

 forth already by Darwin. And farther, these new terms are mostly 

 results of well-known laws and not the primary causes of the formation 

 of varieties or species, and they do not give us a better knowledge than 

 before of the respective processes, in some cases, indeed, they may even 

 induce confusion. 



As respects sepamtion we have seen that Eimer considers it only as an 

 additionalt factor causing specific differentiation, but farther we have 

 seen that his genepistasis is also separation. Like all the other authors 

 he apparently has conceived separation only in a purely geographical 

 sense. I have, however, demonstrated:}: that we are to conceive the term 

 separation in a bionomical sense, that is to say, that any causes "effecting 

 a permanent interruption of the bionomical continuity between certain 

 groups come under the head of separation. Separation keeps particular 

 groups permanently under particular conditions, and thus they are pre- 

 vented from migrating from one station of definite conditions of life into 

 others with other conditions." 



* Eimer identifies Darwin's tlieory witli tlie " Darwinism after Darwin " (comp. Arthildung 

 und Vencandtscfiafl bei Schmetlerlingen, ii, 1895, Preface, p. v), in supposing tliat Darwin's 

 theory alleges that species are formed by natural selection. But we know that this is an 

 entirely unwarranted imputation. 



\See Artbildung, etc., 1895, p. 9. I should like here to point out an apparent error in 

 Eimer's arguments for the origin of new species in the middle of the range of the original 

 form : he says (ibid., p. 11) that the group of Papilio asterias originated from amidst the pro- 

 vince of distriluition of the group of P. machaon. A glance at his tables (PI. vi-viii), 

 however, shows that this is not the case. 



X See Grundzilge, etc., p. 31, and Amer. Jour. Sci., p. 63, et seq , 189G. 



