MODERN BIOLOGY 571 



which the whole theory rests, is called " fnneme.'' Semon adduces a mass of 

 arguments to prove his theory of the transmission of external influence, but 

 all of them have since been rejected or given a fresh interpretation by the 

 representatives of experimental heredity-research. The purely evolutional 

 proofs are borrowed partly from palaeontology — for example, the process 

 of stunted growth in the toes of certain animal forms — and partly from 

 embryology — • the skin of the human sole is even in the embryonic stage 

 thicker than that on other parts of the body — but as these proofs cannot 

 possibly be tested as regards the evolution that has actually taken place, 

 they cannot be considered binding according to exact methods. The experi- 

 mental proofs, however, will be more closely dealt with later on; as a matter 

 of fact, they recur quite regularly in all Lamarckists and are adduced by them 

 as being positive, whereas other investigators have pointed out fallacies 

 either in the experiments themselves or in their interpretations. 



Vauly s Lamar ckism 

 We must mention only in passing one more line of thought based on La- 

 marck, represented, inter alia, by August Pauly (1850-1914), professor at 

 Munich, who seeks the cause of evolution in a conscious psychic striving 

 towards a certain goal on the part of the organism and all its elements. 

 This theory can hardly come within the scope of natural science; it has 

 crossed the border of metaphysics, but is worth mentioning as a further ex- 

 ample of the desperate expedients that the speculation on the problem of 

 origin was finally compelled to adopt. In support of his views Pauly further 

 cites the traditional examples of the inheritance of acquired characters. 



The struggle between the champions and the opponents of the theory 

 of the inheritance of acquired characters is to some extent reminiscent of 

 that between Pasteur and Pouchet regarding spontaneous generation — 

 people could not agree upon the interpretation of the experiments and a 

 theoretical standpoint based on them. And in this case, too, it would seem 

 as if the practical consequences must eventually determine the value of the 

 theory; neither animal-breeders nor horticulturalists have really succeeded 

 in applying the theory of the transmission of acquired characters, those of 

 them who believed in it having really remained at the same grossly empiri- 

 cal standpoint as their colleagues had adopted long before Darwin's time, 

 while modern racial research, working on the Mendelian method, has at- 

 tained results of an entirely different practical value and has, in fact, com- 

 pletely revolutionized the methods of racial breeding. 



Plate s Darwinism 

 While both the theory of selection and Lamarckism thus had their sup- 

 porters, who carried the conclusions of their several lines of thought to ex- 

 treme limits, the middle course pursued by Darwin himself has also been 

 xoUowed by scientists of repute up to modern times. As one of these may be 



