In the main the book is frankly based upon personal experience and observation. It is essentially a record of what I have myself felt and seen. But I have freely availed myself of the experience and writings of others, as reference to the book itself will show. I have tried to be impartial and unbiassed in my researches, and have not “winnowed the facts till only the pleasing ones remained.” At times, indeed, I have found it necessary, while writing this book, to abandon ideas which I had held and promulgated for years. That is an experience not uncommon to those who submit opinions formed as a result of general observation to strict scientific scrutiny. I had long believed and had promulgated the opinion that the great mass of the children of the poor were blighted before they were born. The evidence given before the British Interdepartmental Committee, by recognized leaders of the medical profession in England, pointed to a fundamentally different view. According to that evidence, the number of children born healthy and strong is not greater among the well-to-do classes than among the very poorest. The testimony seemed so conclusive, and the corroboration received from many obstetrical experts in this country was so general, that I was forced to abandon as untenable the theory of antenatal degeneration. In view of the foregoing, I need hardly say that I do not claim any originality for the view that Nature starts all her children, rich and poor, physically equal, and that each generation gets practically a fresh start, unhampered by the diseased and degenerate past.[A] The tremendous sociological significance of this truth—if truth it be—will, I think, be generally recognized. Readers of Ruskin’s _Fors Clavigera_ will remember the story of the dressmaker with a broken thigh, who was told by the doctors in St. Thomas’s Hospital, London, that her bones were in all probability brittle because her _mother’s grandfather_ had been employed in the manufacture of sulphur. If this theory of antenatal degeneration is wrong, and we have not to reckon with grandfathers and great-grandfathers, the solution of the problem of arresting and repairing the deterioration of the race is made so much easier. It may be thought by some readers that I have accepted the brighter, more hopeful view too readily, and with too much confidence. I can only say that I have read all the available evidence upon the other side, and found myself at last obliged to accept the brighter view. I cannot but feel that the actual experience of obstetricians dealing with thousands of natural human births every year is far more valuable and conclusive than any number of artificial experiments upon guinea pigs, mice, or other animals.