176 DARWINISM TO-DAY. 



needed for success in the struggle for existence were not 

 wanting." 



We come now to the second phase of the general objec- 

 tion, as analysed by Plate ; viz., the assumed improbability 

 that during the course of the development 

 Answer to the (evolution) of a complicated or^an or whole 



claimed improb- 



ability of the body-part, or during the perfecting of a chan- 

 time y appear- grins 1 adaptation, the numerous necessary varia- 



ance 01 varia- J 



tions needed in tions \vill occur in such a successive series as 

 structTweJ, 6 to ma ^ e possible an harmonious correlation of 

 the various single variations. Plate writes as 

 follows: 'This objection has been, as is the case with the 

 objection just discussed, raised by many students of evolu- 

 tion as Spencer, Wigand, Nageli, and is in principle not 

 different from the previous objection, but only presents an 

 elaboration of it. It concerns, first, the numerous single 

 variations which are necessary if a single complex organ (as 

 an eye) or a whole body-part with its various organs and 

 tissues (for example, the neck of the giraffe, the fore body 

 of the elk) of a single individual is to be raised to a higher 

 stage of adaptiveness ; and, second, the perfecting of inter- 

 dependent adaptations in different individuals. As example 

 of the latter category I may mention the corolla of flowers 

 and the proboscis of insects which cross-pollinate these 

 flowers, the male and female copulating organs of many 

 animals, as those of the Papilionidse, the adaptations of 

 myrmecophilous and termitophilous animals in relation to 

 their hosts, also those of symbiotic (parasitic or mutualistic) 

 species relative to their companions, and, in cases of mimicry, 

 of the mimicking species relative to the protected species. 

 When one of the species, party to such a mutual adaptation, 

 changes, the other as a rule must also. There arises from 

 this the query : how, in such cases, is there possible the neces- 

 sary coadaptation (coordination), that is, the harmonious 

 change of the parts which produce the interdependent physi- 



