212 MORPHOLOGICAL DEVELOPMENT. 



the evidence furnished by Histology ; nor, indeed, would 

 further examination of this evidence be likely to yield de- 

 finite results. In the cases given above we have marked 

 differences among the incident forces ; and therefore have a 

 chance of finding, as we do find, relations between these and 

 differences of form. But the cells composing masses of 

 tissue are severally subject to forces that are indeterminate ; 

 and therefore the interpretation of their shapes is imprac- 

 ticable. It must suffice that so far as the facts go they are 

 congruous with the hypothesis. 



