14 MARINE BIOLOGICAL LABORATORY. 



The remarkable thing about such an individuality is, 

 that a hundred of them may be added together and the 

 sum total will be but one ; and yet you may divide this 

 one into a hundred ones. 



Mr. Ischikawa succeeded in forcing two individuals 

 into complete and permanent coalescence ; and for 

 aught we can see, the experiment might be repeated 

 indefinitely. One Hydra was turned inside out, and 

 then pushed into the mouth of another until the diges- 

 tive sacks of both were brought together one within the 

 other. A bristle was then thrust transversely through 

 both bodies to prevent separation. In the course of a 

 few days, the two bodies were completely merged in one, 

 and the resulting individual was a perfect personal unity, 

 bearing two sets of tentacles as the only mark of its 

 double origin. 



Having seen in what the essential unity of Hydra 

 consists, we can readily understand why such an indi- 

 viduality may not be weakened by division or strength- 

 ened by doubling. A society of a hundred individuals 

 with ten labors, distributed as we supposed, would rep- 

 resent a unity with ten essential points of union. Now 

 we could double the number of members without in- 

 creasing the points of union ; and we could divide the 

 whole community into ten communities, each with as 

 complete a functional unity as that of all combined. 



In the case of Hydra, we could divide more freely, 

 because the points of union are fewer. Now what I 

 wish to emphasize here is this : TJie mo7'e the points of 

 tmion midtiply in a social or an oi'ga7tic body, the more 

 complex ajtd extended becomes the integration of its parts, 

 and the less susceptible it is to such divisions and fusions 



