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 
