206 Inheritance of Acquired Characters 



For if these structures had all arisen through nat- 

 ural selection only, selecting the most fit from among all 

 the chance variations, one could not explain how, in 

 different species, even though they were subjected in 

 respect to that particular organ to like mechanical con- 

 ditions, it could lead to one and the same result. In 

 fact how could one affirm that the structure of any given 

 organ must be of one certain character only and no other, 

 in order to render the species most fit for the struggle 

 for existence? So mere chance must be invoked to 

 account for the fact that of the numerous structures 

 among which natural selection could choose, it has 

 selected in the most different species subjected to the 

 action of the same mechanical conditions in relation to 

 only one of their organs, just one single structure for 

 this organ, absolutely alike for all these different species. 



A similar phenomenon, which leads one toward the 

 same view, is mentioned by DeVries, as already noted, 

 in support of his theory of pangens or preformistic 

 germs, representative of definite characters ; namely, that 

 the most diverse species of plants have often the power 

 of producing a greater or less number of identical chem- 

 ical compounds. "Insectivorous plants, for example, 

 belong to the most different natural families, neverthe- 

 less they all possess the faculty of producing from their 

 leaves the necessary mixture of an enzyme and an acid 

 requisite for dissolving albuminous bodies." 157 Darwin 

 himself has already remarked that this mixture is quite 

 similar to the gastric juice of the higher animals. 



Now without wishing to touch anew upon the ques- 

 tion of preformistic germs which we have already dis- 



" 7 De Vries : Intracellulare Pangenesis. P. 8 10. 



