122 How Living Things Come to be What They Are 



diflSculties. Indeed many have solved the problem by avoid- 

 ing it. They say in effect there is no becoming; what is al- 

 ways has been. As applied to the process of individual 

 development, this means that whatever is actually present at 

 one stage was also present at each earlier stage even though 

 not apparent to the observer. This view has an ancient and 

 honorable history. Toward the end of the Eighteenth Cen- 

 tury it took definite form in a body of doctrine that for 

 long obstructed scientific progress. 



It is a matter of common observation that the young 

 plant which grows out of the earth when a seed is sown was 

 in reality already present within the seed. In the larger seeds, 

 it is easy enough to distinguish the main axis of the young 

 plant, the root and the shoot, with leaves and a bud. In 

 the bud of a tree before it opens in the spring, it is possible 

 to distinguish clearly enough the shoot and the folded leaflets 

 which expand under favorable conditions of moisture and 

 temperature. Although the parts of a young chicken cannot 

 be seen in the fresh e^g of the hen, it is conceivable that the 

 structures are there. From such facts and considerations 

 arose the notion that the individual exists already formed, 

 but in miniature, in the egg as in the seed. Development 

 came, therefore, to be looked upon as a process of unfolding, 

 and it was to this process that the word evolution was 

 first applied. 



"Within the Egg the Seed 



The doctrine of preformation dominated the minds of 

 thinkers for a long time and gave rise in its turn to another 

 reasonable but today untenable conception. This was the 

 idea that since the egg or the seed, presumed to contain the 

 miniature individual, has come from the parent plant or 

 animal, it must have existed in germ throughout the life of 

 the parent individual, and must therefore have been enclosed 

 in each of the preceding generations. That is to say, the 

 whole human race was already present in the body of Eve, 



