52 MAN [Chap. VIII 



Letter 420 that the effect radiated at first in all directions, and then that 

 certain definite advantageous lines of transmission were 

 acquired, inducing definite reaction in certain lines. Such 

 transmission afterwards became associated in some un- 

 known way with pleasure or pain. These sensations led at 

 first to all sorts of violent action, such as the wriggling of a 

 worm, which was of some use. All the organs of sense would 

 be at the same time excited. Afterwards definite lines of 

 action would be found to be the most useful, and so would be 

 practised. But it is of no use my giving you my crude notions. 



Letter 4*1 To S. Tolver Preston. 



Down, May 22nd, 1880. 



Your letter ! appears to me an interesting and valuable 

 one ; but I have now been working for some years exclu- 

 sively on the physiology of plants, and all other subjects have 

 gone out of my head, and it fatigues me much to try and 

 bring them back again into my head. I am, moreover, at 

 present very busy, as I leave home for a fortnight's rest at 

 the beginning of next week. My conviction as yet remains 

 unchanged, that a man who (for instance) jumps into a river 

 to save a life without a second's reflection (either from an 

 innate tendency or from one gained by habit) is deservedly 

 more honoured than a man who acts deliberately and is 

 conscious, for however short a time, that the risk and sacrifice 

 give him some inward satisfaction. 



You are of course familiar with Herbert Spencer's writings 

 on Ethics. 



1 Mr. Preston wrote (May 20th, 1880) to the effect that "self-interest 

 as a motive for conduct is a thing to be commended — and it certainly 

 [is] I think . . . the only conceivable rational motive of conduct : and 

 always is the tacitly recognised motive in all rational actions." Mr. 

 Preston does not, of course, commend selfishness, which is not true 

 self-interest. 



There seem to be two ways of looking at the case given by Darwin. 

 The man who knows that he is risking his life, — realising that the 

 personal satisfaction that may follow is not worth the risk — is surely 

 admirable from the strength of character that leads him to follow the 

 social instinct against his purely personal inclination. But the man who 

 blindly obeys the social instinct is a more useful member of a social 

 community. He will act with courage where even the strong man 

 will fail. 



