8o 



FACTS AMD FANCIES 



munities ; groups of simple cells which had 

 arisen from the continued division of a single 

 cell remained together, and now began grad- 

 ually to perform different offices of life." 



But this is a mere vague analogy. It does 

 not represent anything actually occurring in 

 nature, except in the case of an embryo pro- 

 duced by some animal which already shows all 

 the tissues which its embryo is destined to re- 

 produce. Thus it establishes no probability 

 of the evolution of complex tissues from sim- 

 ple cells) and leaves altogether unexplained that 

 wonderful process by which the embryo-cell 

 not only divides into many cells, but becomes 

 developed into all the variety of dissimilar tis- 

 sues evolved from the homogeneous ^^^ ; but 

 evolved from it, as we naturally suppose, be- 

 cause of the fact that the ^gg represents po- 

 tentially all these tissues as existing previously 

 in the parent organism. 



But if we are content to waive these objec- 

 tions or to accept the solutions given of them 

 by the ** appearance-and-disappearance " argu- 

 ment, we still find that the phylogeny, unlike 

 the ontogenesis, is full of wide gaps only to be 

 passed /^r saltum or to be accounted for by the 

 disappearance of a vast number of connecting- 



