2 PROBLEMS OF GENETICS 



Darwin and others, but many, especially Darwin himself in his 

 later years, had nevertheless been disposed to depreciate the 

 significance of such facts. They consequently then lapsed into 

 general disparagement. Upon more careful inquiry the abun- 

 dance of such phenomena proved to be far greater than was 

 currently supposed, and a discussion of their nature brought 

 into prominence a consideration of greater weight, namely 

 that the differences by which these definite or discontinuous 

 variations are constituted again and again approximate to and 

 are comparable with the class of differences by which species 

 are distinguished from each other. 



The interest of such observations could no longer be denied. 

 The more they were examined the more apparent it became that 

 by means of the facts of variation a new light was obtained on 

 the physiological composition and capabilities of living things. 

 Genetics thus cease to be merely a method of investigating 

 theories of evolution or of the origin of species but provide a 

 novel and hitherto untried instrument by which the nature of 

 the living organism may be explored. Just as in the study of 

 non-living matter science began by regarding the external 

 properties of weight, opacity, colour, hardness, mode of occur- 

 rence, etc., noting only such evidences of chemical attributes 

 and powers as chance spontaneously revealed; and much later 

 proceeded to the discovery that these casual manifestations of 

 chemical properties, rightly interpreted, afford a key to the 

 intrinsic nature of the diversity of matter, so in biology, having 

 examined those features of living things which ordinary obser- 

 vations can perceive, we come at last to realize that when studied 

 for their own sake the properties of living organisms in respect 

 of heredity and variation are indications of their inner nature 

 and provide evidences of that nature which can be obtained from 

 no other source. 



While such ideas were gradually forming in our minds, came 

 the rediscovery of Mendel's work. Investigations which before 

 had only been imagined as desirable now became easy to pursue, 

 and questions as to the genetic inter-relations and compositions 

 of varieties can now be definitely answered. Without prejudice 



