CHAPTER XII. 



RECAPITULATION AND CONCLUSION. 



THE obscurity and complexity of the phenomena of 

 heredity afford no ground for the belief that the subject 

 is outside the legitimate province of scientific inquiry. 

 The existence, in a simple and unspecialized egg, of the 

 potentiality of a highly organized and delicately adjusted 

 animal, with special functions, instincts and powers of 

 adaptation, with the capacity for establishing and per- 

 petuating harmonious relations to the changing con- 

 ditions of the world around it, is certainly one of the 

 most profound problems of the material universe. 



The fertilized egg is one of the greatest wonders with- 

 in our knowledge, but this is no reason for refraining 

 from studying it. 



If we believe that living things have become what they 

 now are by a process of gradual evolution, and that they 

 owe their characteristics to the influences to which they 

 have been exposed in the past, we must believe that the 

 properties of the egg are capable of explanation, as far as 

 these determining causes are open to study. 



If we accept the generalizations of modern science, 

 and hold that an unicellular ovum is homologous with 

 and is descended from a remote ancestral unicellular 

 organism, and that its properties have been gradually 

 acquired by the natural selection of favorable variations, 

 we must believe that the origin of its properties is as 

 much within our reach as the origin of species. 



The most prominent characteristic of heredity is that 



