260 TEE INDUCTIONS OF BIOLOGY. 



gemmation from a parent organism, passes gradually from a 

 state in which it is an indistinguishable part of the parent 

 organism to a state in which it is a separate organism of like 

 structure with the parent. At what stage does it become an 

 individual? And if its individuality be conceded only when 

 it completely separates from the parent, must we deny indi- 

 viduality to all organisms thus produced which permanently 

 retain their connexions with their parents? Or again, what 

 must we say of the Ilectocotylus, which is an arm of the 

 Cuttle-fish that undergoes a special development and then, 

 detaching itself, lives independently for a considerable 

 period ? And what must we say of the larval nemertine worm 

 the pilidium of which with its nervous system is left to move 

 about awhile after the developing worm has dropped out 

 of it? 



To answer such questions we must revert to the definition 

 of Life. The distinction between individual in its biological 

 sense, and individual in its more general sense, must consist 

 in the manifestation of Life, properly so called. Life we 

 have seen to be, " the definite combination of heterogeneous 

 changes, both simultaneous and successive, in correspondence 

 with external co-existences and sequences." Hence, a bio- 

 logical individual is any concrete whole having a structure 

 which enables it, when placed in appropriate conditions, to 

 continuously adjust its internal relations to external relations, 

 so as to maintain the equilibrium of its functions. In 



pursuance of this conception, we must consider as individuals 

 all those wholly or partially independent organized masses 

 which arise by multicentral and multiaxial development that 

 is either continuous or discontinuous (§ 50). W^e must accord 

 the title to each separate aphis, each polype of a polypedom, 

 each bud or shoot of a flowering plant, whether it detaches 

 itself as a bulbil or remains attached as a branch. 



By thus interpreting the facts we do not, indeed, avoid all 

 anomalies. While, among flowering plants, the power of 

 independent growth and development is usually possessed 



