Community Life in the Animal Kingdom. 9 



live together from immediate, vegetative necessity; 

 for they literally grow as branches from a common 

 trunk. As it is an immediate vegetative necessity for 

 plants to bring forth twigs, leaves and blossoms, so 

 mere vegetative necessity forces a colony of Siphono- 

 phores to separate into different loosely connected 

 individuals, some serving the purpose of nutrition 

 (nutrient polyps), others of propagation (sexual 

 polyps), of perception (perception polyps), of loco- 

 motion (swimming polyps), and of protection (pro- 

 tective polyps). To apply to the members of such 

 colonies the term "persons" (eating persons, swim- 

 ming persons, etc.), as Haeckel and several other 

 zoologists have done, is evidently out of place, because 

 this term implies a psychic independence which these 

 animals do not possess. It would be more justifiable 

 to conceive the whole growth of Siphonophores as 

 one individual of imperfect unity, consisting of various 

 members, which, on account of their different func- 

 tions can more fitly be termed "organs" than "persons." 



The similarity of social life in the colonies of 

 polyps and of ants is very slight and superficial. The 

 latter, in opposition to the former, consists of indi- 

 viduals organically separated and independent in their 

 psychic activities. The members of an ant colony are 

 complete individuals united to each other, not by the 

 laws of vegetative growth, but by instinctive sym- 

 pathy. This kind of co-habitation must indeed be 

 regarded as a higher manifestation of psychic life 

 unknown among solitary animals. 



It is true, with the state-forming insects also, the 

 instinctive association of the individuals of a colony 



