OONFOBMITY TO ENVIBONMENT 193 



" A little leaven leaveneth the whole lump." " Not 

 by might, nor by power, but by my Spirit, saith the 

 Lord of Hosts." 



But, you will object, the grandest kings have had, 

 as a rule, the fewest loyal subjects. The prophets and 

 seers are stoned. Elijah stands alone on Carmel and 

 opposed to him are more than a thousand prophets of 

 Baal, with court and king at their head. Heroism 

 does not pay, and heroes are few. Eight is always in 

 a hopeless minority. Let us look into this matter 

 carefully, for the objection, even if overstated, certainly 

 contains a large amount of truth. 



Let us go back to two forms having much the same 

 grade of organization : both worms. One of them 

 sets out to become a vertebrate, building an internal 

 skeleton. The other forms an external skeleton and 

 becomes a crab. To form its skeleton the crab had 

 only to thicken the cuticle already present in the an- 

 nelid. It had to modify the already existing parapodia 

 and their muscles, changing them to legs. The ex- 

 ternal skeleton gave from the start a double advantage 

 — protection and better locomotion. Every grain of 

 thickening aided the animal in the struggle for ex- 

 istence in both these ways. The very fact that the 

 skeleton was external may have rendered it more 

 liable \,o variation, because it was thus exposed to 

 continual stimuli. And the best were rapidly sifted 

 out by Natural Selection. The change and develop- 

 ment went on with comparative rapidity. In the 

 mollusk the change was apparently still more easy and 

 the development still more rapid. 



But the development of an internal skeleton was 

 more diiScult and slower. It was of no use for the 

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