2 24 THE HISTORY OF CREATION. 



The first series, comprising the phenomena of indirect 

 (potential) adaptation, has, on the whole, hitherto been 

 little attended to, and Darwin has the merit of having 

 directed special attention to this series of changes. It is some- 

 what difficult to place this subject clearly before the reader ; 

 I will endeavour to rhake it clear hereafter by examples. 

 Speaking quite generally, indirect or potential adaptation 

 consists in the fact that certain changes in the organism, 

 effected by the influence of nutrition (in its widest sense) and 

 of the external conditions of existence in general, show them- 

 selves not in the individual form of the respective organism, 

 but in that of its descendants. Thus, especially in organisms 

 propagating themselves in a sexual way, the reproductive 

 sj^stem, or sexual apparatus, is often influenced by external 

 causes (which little aflect the rest of the organism), to such a 

 degree that its descendants show a complete alteration of 

 form. This can be seen very strikingly in artificially pro- 

 duced monstrosities. Monstrosities can be produced by sub- 

 jecting the parental organism to certain extraordinary con- 

 ditions of life, and, curiously enough, such an extraordinary 

 condition of life does not produce a change of the organ- 

 ism itself, but a change in its descendants. This cannot be 

 called transmission by inheritance, because it is not a quality 

 existing in the parental organism that is transmitted by 

 inheritance. It is, on the contrary, a change aflfecting the 

 parental organism, but not perceptible in it, that appears in 

 the peculiar formation of its descendants. It is only the 

 impulse to this new formation which is transmitted in pro- 

 pagation through the egg of the mother or the sperm of 

 the father. The new formation exists in the parental 

 organism only as a possibility (potential) ; in the descend- 

 ants it becomes a reality (actual). 



