`Then why write of it, you may ask? If a subject is painful why treat it at all? I answer that it is the province of fiction to treat painful things as well as cheerful ones. The story which wiles away a weary hour fulfils an obviously good purpose, but not more so, I hold, than that which helps to emphasise the graver side of life. A tale which may startle the reader out of his usual grooves of thought, and shocks him into seriousness, plays the part of the alterative and tonic in medicine, bitter to the taste but bracing in its result. There are a few stories in this little collection which might have such an effect, and I have so far shared in your feeling that I have reserved them from serial publication. In book form the reader can see that they are medical stories, and can, if he or she be so minded, avoid them.—Yours very truly,
`A. Conan Doyle.
`P. S.—You will see that nearly half of the contents have not appeared before.'
