PART FIVE 



The Nature of the Gene 



One of the ultimate aims of genetics must be the elucidation of the 

 nature of the gene, but science is still very far from attaining this goal. 

 We can only approach the problem in several rather indirect ways. 

 Firstly, we can investigate the nature of the chromosomes with which 

 the genes are so intimately associated. Secondly, we can consider the 

 developmental reactions determined by genes. Thirdly, there are some 

 general genetical phenomena which have suggested hypotheses as to the 

 nature of the gene. Fourthly, we can investigate gene mutation and 

 particularly the induction of mutation by experimental means. In this 

 part, these methods of approach are considered in order, and in the last 

 two sections an attempt is made to formulate the chemical problems 

 which are implicit in our knowledge of gene behaviour. 



