Consideration of Weismann' s Arguments 187 



to a large number of modifications, which do not differ 

 in their essence from the others, the character of func- 

 tional adaptations. We would not deny that there are 

 certain forms or structures, which, just because their 

 functional character has not been perceived, have not 

 heretofore received any explanation except through nat- 

 ural selection, even though it does not always furnish 

 an altogether satisfactory explanation. But the deeper 

 one goes into the essence of functional adaptation and 

 the wider its field of action is seen to be, the number of 

 these formations become less and less and with it 

 dwindles away also this seeming almightiness to explain 

 all physiologic transformations whatever, which Weis- 

 mann would like to attribute to natural selection without 

 producing proof for it. 



3. The third argument based upon the neutral indi- 

 viduals of ants, bees and termites is well known as the 

 chief question about which turned the polemic between 

 Weismann and Spencer. The latter brought up as one 

 of the strongest arguments in favor of inheritance, the 

 co-adaptation, that is the co-ordinated modification of 

 different parts co-operating to produce a definite physio- 

 logical result. Weismann on the contrary sees in the 

 existence of neutral individuals among the ants, termites 

 and bees a refutation of Spencer's theory, since these 

 individuals in the course of their phylogenetic develop- 

 ment have undergone harmonious modifications of di- ' 

 verse parts, without ever having been capable of repro- 

 duction. To this Spencer replied that all the harmonious 

 modifications of different parts, including the numerous ' 

 instincts which the neutrals present to-day, are only the 

 heritage of those which the ancestors of these now social 

 insects acquired in a state of isolation or in a society in 



