n] BIOLOGICAL FOUNDATIONS 43 



limit, they repeat the process. Division is thus even 

 more important for the present purpose than budding ; 

 we have the strange paradox that though each in- 

 dividual hands on the whole of its substance intact 

 to its successors, yet with this perfect continuity of 

 substance there co-exists perfect discontinuity of 

 individualities. 



There remains the third chief mode of reproduc- 

 tion. In considering the hydroid colony, we found 

 that all its members took their origin, by budding, 

 from one single founder. This founder, though 

 identical in organization with the rest, has yet not 

 had the same origin as they. Tracing its life back- 

 ward towards its source, we find it first of smaller 

 size; then comes the stage when its organs are 

 developed one by one, much as in the bud ; before 

 this it exists in a form through which the budded 

 individuals never pass as a small drawn-out ovoid, 

 actively swimming instead of fixed to the ground; 

 before this again it is seen as a round motionless 

 body, built up like a mulberry out of rounded parts, 

 and finally its "fount of life" is revealed in a spherical, 

 inert mass, single and undivided the fertilized egg. 



This fertilized egg is neither more nor less than 

 a cell specialized, as one would expect, for the 

 discharge of its own particular duties, but still a cell. 

 Here is a further strengthening of our view of the 

 higher animal or metazoan as a colony of units each 



