f 



I.! 



78 



FACTS ^ND FANCIES 



fact, quite dissimilar. There is, indeed, the best 

 ground to suppose that the one-celled animals 

 and the embryo-cells referred to, have little in 

 common except their general form. We know 

 that the most minute cell must include a suf- 

 ficient number of molecules of protoplasm to 

 admit of great varieties of possible arrange- 

 ment, and that these may be connected with 

 most varied possibilities as to the action of 

 forces. Further, the embryo-cell which is pro- 

 duced by a particular kind of animal, and whose 

 development results in the reproduction of a 

 similar animal, must contain potentially the 

 parts and structures which are evolved from 

 it ; and fact shows that this may be affirmed of 

 both the embryo and the sperm-cells where 

 there are two sexes. Therefore it is in the 

 highest degree probable that the eggs of a 

 worm and those of man, though possibly alike 

 to our coarse methods of investigation, are as 

 dissimilar as the animals that result from them. 

 If so, the " ^^g may be before the hen ;" but it 

 is as difficult to imagine the spontaneous pro- 

 duction of the ^^^ which is potentially the hen 

 as of the hen itself. Thus the similarity of the 

 eggs and early embryos of animals of different 

 grades is apparent only; and this fact, which 



