INTERNAL CAUSES OF VARIATION 207 



point many times, and in numerous cases with effect, but mam- 

 mals as a race have been able to endure the handicap, else they 

 would long since have become extinct. 



This shows that some causes other than utility are responsible 

 for the appearance and continuance of racial characters; that 

 teleology 1 is not a universal principle, and that the function of 

 selection is restrictive, not creative. 



Other characters not teleological may easily be mentioned : 



1. The peculiar minute markings on diatoms and on other 

 inconspicuous organisms. 



2. The green color of leaves, due simply to the fact that 

 chlorophyll is green. This is no more of an inherent necessity 

 than that coal should be black or gold yellow. 



3. The digital number five which runs generally through 

 vertebrates, which has often been modified and often left intact. 

 Certainly the original number five could not have been teleolog- 

 ical. It is not enough to assume that changed conditions might 

 have rendered an organ detrimental which was once useful. 

 There are too many obviously useless characters. 



4. The phosphorescence of pelagic animals, 2 and the pearl of 

 the oyster, which is due to injury. Is this beauty useful or is it 

 accidental ? 3 



5. The bright color of deep-sea fishes. Is it any more signifi- 

 cant than the (accidental) color of chlorophyll-bearing leaves ? * 



6. The horns of stags, useful (?) in battle, but weapons as 

 dangerous to the possessor as to his enemy. 



The list might be extended indefinitely. Eimer 's argument is 

 that characters such as these have been produced not through 

 selection but in spite of it, and through the agency of organic 

 growth in definite directions, which is orthogenesis. It w.ould be 

 difficult to be always certain that no basis of utility exists or 

 ever has existed simply because it is not now evident, yet no 



1 The doctrine that development is in line with utility and that everything is 

 useful is known as " teleology." 



2 Eimer, Organic Evolution, p. xiii. 



3 Eimer, Orthogenesis, p. 10. 



4 In certain leaves of bright color the chlorophyll is unable to dominate the 

 stronger shades of other chemical substances, and the leaf is not green but some 

 other color. 



