206 ROUGH WAYS MADE SMOOTH. 



deavour to ascertain their real cause. In their case we can 

 ascertain the ' how/ but in no sense the ' why.' Gravity is a 

 mystery of mysteries to the astronomer, and has almost 

 compelled us to believe in that ' action at a distance ' which 

 Newton asserted to be unimaginable by anyone with a com- 

 petent power of reasoning about things philosophical. The 

 ultimate cause of chemical changes is as great a mystery 

 now as it was when the four elements were believed in. 

 And the nature of the ether itself in which the undulations 

 of heat, light, and electricity are transmitted is utterly 

 mysterious even to those students of science who have been 

 most successful in determining the laws according to which 

 those undulations proceed. But the phenomena themselves 

 being at once referable (in our own time at least) to law, 

 have no longer the mysterious and in a sense miraculous 

 character recognised in them before the laws of motion, of 

 chemical affinity, of light and heat and electricity, had been 

 ascertained. It is quite otherwise with the phenomena of 

 heredity. We know nothing even of the proximate cause 

 of any single phenomenon ; far less of that ultimate cause 

 in which all these phenomena had their origin. The in- 

 heritance of a trait of bodily figure, character, or manner is 

 a mystery as great as that other and cognate mystery, the 

 appearance of some seemingly sudden variation in a race 

 which has for many generations presented an apparently 

 unvarying succession of attributes, bodily, physical, or 

 mental. 



It need hardly be said that this would not be the place 

 for the discussion of the problems of heredity and variation, 

 even if in the present position of science we could hope for 

 any profitable result from the investigation of either subject. 

 But some of the curious facts which have been noted by 

 various students of heredity will, I think, be found inte- 

 resting ; and though not suggesting in the remotest degree 

 any solution of the real difficulties of the subject, they may 

 afford some indication of the laws according to which 



