iv] THE SECOND GRADE 97 



itself out, and the collar-cells (till now quiescent, with 

 collar and flagellum withdrawn) arrange themselves 

 in a single layer round the cavity, and become active 

 once more. Finally an osculum and pores are de- 

 veloped and the random collection of cells (though 

 by processes not seen in normal development) has 

 become an actual sponge, living and functioning, 

 similar in every way to one that has grown up from 

 the egg. 



Of the two experiments, the first is the more 

 surprising, the second the more mysterious. In the 

 first, a new form of life is produced something- 

 capable of living, that is, and yet in its structure 

 unlike any known animal : but, given the large 

 degree of independence possessed by the cells, the 

 rest follows naturally. In the second, however, there 

 seems to be a strange organizing power superior in 

 kind to the powers of the cells themselves an idea 

 of the whole, informing the parts. Again the image 

 of a general directing his army, even of an architect 

 arranging his materials, springs to the mind : but 

 again, where is the general, where the architect? 

 There is no possibility of anything thus extraneous 

 existing in the normal sponge, still less in the 

 little balls, composed as they are of random cells 

 in random grouping. However, the nature of this 

 directive power we must leave for later consideration 

 (p. 146). Here it suffices to have shown that it exists. 



H. 7 



