28 Heredity. 



So far as it is a statement of facts, it cannot be called 

 an hypothesis, for it simply affirms that the Qg'g is opti- 

 cally an ordinary nnspecialized cell; that it gives rise, 

 during the j^rocess of segmentation, in a manner which is 

 identical with ordinary growth by cell division, to a num^ 

 bcr of cells which gradually become specialized for cer- 

 tain functions, and are set apart as the foundations of the 

 various organs of the body; that the repetition of this 

 process gives rise, at last, to the perfect body of the 

 mature animal; that the reproductive elements which are 

 to give rise to the next generation, originate, like all the 

 cells of the body, by cell division during the process of 

 development, and that they are simply cells specialized for 

 the reproductive function as other cells are specialized for 

 other functions. Every one who has the slightest ac- 

 quaintance with modern biology will accept this state- 

 ment, not as an hyjDothesis, but as an observed fact, and 

 will agree that between this and the old evolution hy- 

 pothesis there can be but one choice. 



The old hypothesis of evolution, however, claimed to 

 be something more than a statement of fact, for the 

 presence of the germ within the Qgg accounted for the 

 wonderful properties of the Qgg itself. 



We are at once compelled to ask, then, how, on the 

 hypothesis of epigenesis, has the egg acquired these prop- 

 erties ? If it is simply an nns2:)ecialized cell; if, as Ge- 

 genbauer states, '* the ^gg is nothing more nor less than 

 a cell; the egg-cell does not differ from other cells in 

 any essential points" (Comp. Anat., Bell's Trans., p. 18), 

 how can the ^gg of a horse develop into a horse, while 

 another cell, which ^'does not differ from it in any essen- 

 tial points," develojDS into a bee or an alligator or an 

 oyster ? 



Nothing in nature is more marvellous than the devel- 



