THE CELLULAR BASIS 161 



are not wholly lost. In short, the specificity 

 of the germ applies not merely to those things 

 in which it differs from other 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 

 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 trans- 

 formation of the specific characters of the germ 

 into those of the adult, but not in the formation 

 of structures or characters de novo. From be- 

 ginning to end development is a series of mor- 

 phological and physiological changes but not 

 of new formations or creations. It is only the 

 incompleteness of our knowledge of develop- 

 ment 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. 



