x AUTHOR'S PREFACE 



complex phenomena of sociology many conclusions as to 

 social diagnosis which only extended labour could make 

 quite clear. Although I cannot carry out the labour 

 originally proposed, such investigations as I have been 

 able to make may throw a useful light on the funda- 

 mental principles of social adaptation, and also discover and 

 illuminate a number of vexed questions in biology. It 

 would be ungrateful of me if I did not acknowledge that 

 the impulse to attempt such a task sprang, not, as might 

 possibly be imagined, from the work of Herbert Spencer, 

 but from a little-known book by a great physician, who 

 never received his full meed of appreciation as a teacher. 

 I refer to the late Dr. Henry Gawen Sutton, once a colleague 

 of Sir Andrew Clark's at the London Hospital, whose 

 Lectures on Pathology, taken down by an ardent student, 

 contain a sounder criticism of life and more real wisdom 

 than a library of metaphysical treatises. His pathology 

 may, indeed, be out of date, but the knowledge that has 

 passed him by has not yet reached the height of his vision, 

 since his intuition, though sometimes curiously and 

 roughly phrased, often condensed into five words the life- 

 time's thinking of a true philosopher. 



It is generally supposed that any one who is outside 

 the circle of professional investigation, and attempts to 

 enter it with no credentials, does so at the peril of entire 

 neglect if not of contumely. On this point I can only say, 

 and I do so with gratitude, that the encouragement received 

 from most of those best qualified to speak upon the subjects 

 treated has been most generous, while the exceptions to the 

 general rule are so few that the very fact of their existence 



