5i8 THE WONDlR OF LIFE 



Finally, in thinking over this difficult problem of adapta- 

 tions, we must remember the importance of the active 

 organism itself. As Professor James Ward has well pointed 

 out, it may seek out and even in part make its environment ; 

 it is not only selected, it selects ; it acts as well as reacts. 

 And although the details and finesse of this may have been 

 elaborated in the course of selection, the primary poten- 

 tiality of it is an essential part of the secret of that kind 

 of activity which we call Life. 



Illustrations of Adaptations. — The structure of a long 

 bone in a mammal is adapted to give the utmost firmness 

 with the minimum expenditure of material ; the unique 

 pollen-basket on the hind legs of worker-bees is adapted 

 to stow away the pollen ; the colours and patterns on the 

 wings of leaf-insects are adapted to harmonize with the 

 foHage on which they settle ; the parts of flowers are often 

 adapted to ensure that the insect- visitors are dusted with 

 pollen, and thus to secure cross-fertihzation ; the peacock 

 is adapted to captivate the pea-hen ; the mother mammal 

 is adapted for the prolonged pre-natal life of the young ; 

 the so-called ' egg- tooth ' at the end of a young bird's bill 

 is adapted to the single operation of breaking the egg-shell 

 — and so on throughout the whole of the animate world. It 

 is indeed a mistake to dwell upon signal instances of adapta- 

 tions, since (apart from degenerative changes in old age, 

 morbid processes, perverted instincts, rudimentary or 

 vestigial structures, and certain ' indifferent ' characters 

 which are not known to have any vital significance) almost 

 every detail of structure and function may be regarded as 

 adaptive. 



The Mole. — In illustration of adaptive characters let 

 us consider a common animal hke the mole, ' the httle 



