Fission and Gemmation in the Animal Kingdom. 39 



It follows as a matter of course from what has been stated 

 that gemmation bj no means excludes the direct transition of 

 a portion of the parent into the rudiment of tiie bud. As a 

 matter of fact this actually occurs in the reproduction of 

 certain Stony Corals, for an account of which we are indebted 

 to the beautiful investigations of von Koch *. 



In the foregoing statements as to fission and gemmation I 

 have, in order to avoid too great complication of the progress 

 of the discussion, disregarded a circumstance which never- 

 theless requires to be shortly considered in order to complete 

 the views which we have gained, i. e. the question of indi- 

 viduality. 



Ha3ckel was probably the first to establish the fact that, 

 contrary to what happens in the case of fission, which 

 disposes of the original parent-form, the individuality of the 

 bud-producing animal is preserved unaltered. The general 

 truth of this proposition is beyond question ; in the case of 

 gemmation it is proved by experience, in that of fission it is 

 a priori a logical necessity. Nevertheless it appears to rae 

 to be desirable to trace the change of individuality, at least 

 in the case of those " successive " fissions {str oh ilat ion-form 

 of fission sensli latiori) which are of such frequent occur- 

 rence. In so doing I have no intention of entering at length 

 into the theory of animal individuality; on the contrary, it 

 is sufficient for our purpose to proceed from more general 

 experience and considerations. 



(Starting from the fact that in many animals " the single 

 individual can be split up by means of artificial division into 

 several individuals which continue an uninterrupted exist- 

 ence," it was shown by Goette "that this divisibility is neither 

 unlimited nor unconditional, but is without exception accom- 

 panied by the fact that the parts possess the structural con- 

 ditions of the whole, and moreover the power of preserving 

 them in integral continuity — that, in other words, they are 

 capable of providing in themselves a complete repetition of 

 the original whole ; ' individuality ' of organisms therefore 

 does not signify absolutely an indivisibility, but rather only 

 such as maintains the integrity of a vital unit or of a conunou 

 life, and at the same time the possibility of an independent 

 existence ^' f. 



Goette therefore sees in individuality the " condition of 



* G. V. Koch, " Die ungeschl. Vermehruug einiger paliiozoisclior Koral- 

 len vergleicbeud betrachtet," Palaontographica, lid. 29, pp. ^41 et sqq. 



t A. Goette, ' Ueber den Ursprung des Todos,' Leipzig, 1883, pp. 12 

 et sqq. 



