Fortschritte unserer Anschauungen über Deszendenz seit Darwin usw. 385 



„The facts force us to the conclusion, that in the germ there 

 must be present things, which have been derived from the parent 

 and are responsible, when present in the offspring of making the 

 individual develop differently from such a lack as this thing." 



„We know further that an individual which has derived 

 some of this inheritable something from at least one of its parents, 

 therefore originally not more of it as can be present in this 

 germcell can produce so much of it, that it can furnish at least 

 50 Proc. of its germcells with enough of it to call forth the corre- 

 sponding difference in development of the resulting organisms." 



„We also know that in many cases (it is merely a tech- 

 nical difficulty Avhich prevents us from verifying this for all cases) 

 these inheritable things must be present in all the cells of the 

 individual (one epidermis-cell of Begonia can give rise to a com- 

 plete plant) we are therefore forced to admit that the inheritable 

 thing, with which we are dealing is capable of reproducing 

 its kind." 



Ganz richtig ist auch folgendes: 



„The hypothesis that these hereditary things are vital 

 units, composed of protoplasm and capable of assimilation and 

 growth, certainly fits the facts, but we ask more of a theorj^ 

 of heredity and evolution. A working-hj-pothesis to be of any 

 use as an instrument of research must explain the facts in 

 terms of what is already known. It ist inadmissable to ivy to 

 explain the facts of evolution and inheritance by the behaviour 

 of living particles which have been invented simply to admit 

 of this explanation." 



Dann sagt er: 



„We must again look to the facts to try and find whether 

 there is not a possibility, that not the living being and „there- 

 fore" all the causating agents for its characters are living things, 

 but that the organisms are living because the fact that they 

 have all these characters" (besser wäre wohl: because they have 

 the causating agents for these characters)," 



What then is the nature of these genetic factors, fragt Hage- 

 doorn und meint: 



„the hereditary factors for the development of an organism 

 are numerous independantly transmitted substances, each having 

 autokatalytical properties." 



Das ist, wie er selber sagt, „simply a modification of the hypo- 

 theses of Loeb and Roux, necessitated by the facts of Mendelian 

 inheritance." 



25* 



