GERMINAL SELECTION. 35 



itary diathesis, the constitutional predisposition 

 (Anlagc) of the breed was changed in the respect in 

 question, and our conclusion from this and numerous 

 similar facts of artificial selection runs as follows : by 

 the selection alone of the plus or minus variations of a 

 character is the constant modification of that character 

 in the plus or minus direction determined. Obviously 

 the hereditary diminution of a part is also effected 

 by the simple selection of the individuals in each gen- 

 eration possessing the smallest parts, as is proved, for 

 example, by the tiny bills and feet of numerous breeds 

 of doves. We may assert, therefore, in general terms : 

 a definitely directed progressive variation of a given 

 part is produced by continued selection in that definite 

 direction. This is no hypothesis, but a direct inference 

 from the facts and may also be expressed as follows: 

 By a selection of the kind referred to the germ is pro- 

 gressively modified in a manner corresponding with 

 the production of a definitely directed progressive 

 variation of the part. 



In this general form the proposition is not likely to 

 encounter opposition, as certainly no one is prepared 

 to uphold the view that the germ remains unchanged 

 whilst the products proceeding from it, its descend- 

 ants, are modified. On the contrary, all will agree 

 when I say that the germ in this case must have under- 

 gone modifications, -and that their character must cor- 

 respond with the modifications undergone by its prod- 

 ucts. Thus far, then, we find ourselves, not on the 

 ground of the hypothesis that has been lately so much 

 maligned, but on the ground of facts and of direct 

 inferences from facts. But if we attempt to pierce 

 deeper into the problem, we are in need of the hy- 

 pothesis. 



