PllIMITlVJ!: MAN. 833 



place. Besides, the seed itself is not a tiling self- 

 existent cr fortuitous. Tlie production of a seed 

 without a previous tree of the same kind is quite as 

 difficult to suppose as the production of a tree with- 

 out a previous seed containing its living embryo. In 

 the third place, the whole argument is one of analogy. 

 The germ becomes a mature animal, passing through 

 many intermediate stages, therefore the animal may 

 have descended from some creature which when 

 mature was as simple as the germ. The value of 

 such an analogy depends altogether on the similarity 

 of the ^' conditions,'^ which, in such a case, are really 

 the efficient causes at work. The germ of a mammal 

 becomes developed by the nourishment supplied from 

 the system of a parent, which itself produced the 

 germ, and into whose likeness the young animal is 

 destined to grow. These p.re the '^appropriate con- 

 ditions'' of its development. But when our author 

 assumes from this other " appropriate conditions," by 

 which an organism, which on the hypothesis is not a 

 germ but a mature animal, shall be developed into the 

 likeness of something different from its parent, he 

 oversteps the bounds of legitimate analogy. Further, 

 the reproduction of the animal, as observed, is a 

 closed series, beginning at the embryo and returning 

 thither again ; the evolution attempted to be estab- 

 lished is a progressive series going on from one stage 

 to another. A reproductive circle once established 

 obeys certain definite laws, but its origin, or how it 

 can leave its orbit and revolve in some other, we 



