230 MORPHOLOGICAL DEVELOPMENT. 



the evidence furnished by Histology; nor, indeed, would 

 further examination of this evidence be likely to yield 

 definite 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 which are indeterminate; 

 and therefore the interpretation of their shapes is imprac- 

 ticable. It must suffice to observe that so far as the facts go 

 they are congruous with the hypothesis. 



