The Cellular Basts 175 



the specificity of the germ applies not merely to those things in 



which it differs from oilier germs, but also to characters in which 

 it resembles others; in short, to hereditary resemblances no less 

 than to hereditary differences. 



The mistake of the doctrine of preformation (see p. 57) was 

 in supposing that germinal parts were of the same kind as adult 

 parts; the mistake of epigenesis was in maintaining the lack of 

 specific parts in the germ. The development of every animal and 

 plant consists in the transformation of the specific characters of 

 the germ into those of the adult. From beginning to end de- 

 velopment is a series of morphological and physiological changes 

 but not of new formations or creations except in so far as new 

 structures or functions appear as a result of "creative synthesis." 

 It is only the incompleteness of our knowledge of development 

 which allows us to say that the eye or ear or brain begins to 

 form in this or that stage. They become visible at certain stages, 

 but their real beginnings are indefinitely remote. 



II. Correlations Between Germinal and Somatic 



Organization 



All the world knows that the organization of the germ is not 

 the same as that of the developed animal which comes from it, and 

 yet the specificity of the germ indicates that there must be some 

 correlation between the germinal and the developed organization ; 

 in short, there is not identity of organization but correlation of 

 organization between the germ and the adult. What correlations 

 are known to exist between the oosperm and the developed ani- 

 mal ? 



Inheritance Factors and Developed Characters. — We have con- 

 sidered in the preceding chapter (pp. 99-104) the evidence that 

 there are specific inheritance factors or genes which are correlated 

 with the development of specific adult characters. These factors 

 are not the characters in miniature nor are they the ''representa- 

 tives" or "carriers" of characters, but they are the differential 

 causes of characters. Every inherited character must have a 



