ceed blindly or aimlessly, but proceeds on rigidly determ- 

 ined lines, whicJi depend upon the structure and constitu- 

 tion of the particular organism. External influences, how- 

 ever, also affect it. Eimer specially emphasizes four points 

 in this connection: i. This rigidly determined develop- 

 ment of a character exhibits well defined, regular 

 stages, and the evolution of each individual repeats the 

 whole series of transformations (the Mueller-Haeckel 

 "biogenetic-law." 2. New characters are first acquired by 

 strong adult males (the law of male dominance). 3. New 

 characters appear on definite parts of the body, spreading 

 especially from the rear to the front, (the law of undula- 

 tion). 4. Varieties are stages in the process of develop- 

 ment, through which all the individuals of thet respective 

 species must pass. M«"^ l-i^.U- 



These points indicate how important for Eimer is the 

 transmission of those characters which the parents 

 themselves have acquired in the course of their own devel- 

 opm.ent. He conceives that this transmission takes place 

 when the causative influences exert themselves permanently 

 on many succeeding generations. Eimer thinks that in this 

 way the constitution of the respective species is gradually 

 transformed. Besides the effect of external influences 

 (which may vary according to the climate, etc.: Geoffroy 

 St. Hilaire), Eimer mentions as important and active fac- 

 tors in this development, (i). The use and disuse of organs 

 (Lamarck); (2). The struggle for existence (Darwin); (3). 

 The correlation of organs, that is, the inner relation of or- 

 gans in consequence of which a change in one organ may 



70 



