This section is from the book "Married Love: A New Contribution to the Solution of Sex Difficulties", by Marie Carmichael Stopes. Also available from Amazon: Married Love: A New Contribution to the Solution of Sex Difficulties.
Gower Street, London, W.C., November 23, 1917. Dear Dr. Stopes,-The need of such guidance as you give is very evident. After all, instinct in man is all insufficient to determine social behaviour, and there is need of instruction in the highest of physiological functions, that of reproduction, as there is in the lower functions of eating and drinking --the only difference being that in the former instruction can be deferred to a later age. And there is no doubt that in this case it is better to acquire knowledge by instruction than by a type of experience which is nearly always sordid and may be fraught with danger to the health of the individual and of the family.
If your book helps in securing this object, your trouble not have been in vain.
Yours very truly, Ernest H. Starling.