《血字的研究(英文)》是英国推理小说家阿瑟·柯南·道尔于1887年创作的中篇小说,这也是他首本以歇洛克·福尔摩斯为主角的作品。

“You see,” he explained, “I consider that a man's brain originally is like a little empty room, and you have to stock it with such furniture as you choose. A fool takes in all the junk he comes across, so that the knowledge which might be useful to him gets crowded out, or at best is mixed up with a lot of other things so that he has difficulty in finding it. Now the expert worker is very careful indeed as to what he takes into his brain. He will have nothing but the tools which may help him in doing his work, and he has a large collection of these tools, but all in the most perfect order. The 'room' in one's brain is of fixed and limited size, so there comes a time when, for every addition of knowledge, you forget something that you knew before. It is of the highest importance,therefore, not to have useless facts pushing out the useful ones.”
“But the Solar System!” I protested.
“What is it to me?” he said impatiendy “You say that we go round the sun. If we went round the moon, it would make no difference to me or to my work “
I was on the point of asking him what that work might be, but something in his manner showed me that the question would be an unwelcome one.
During the first week or so we had no visitors, and I had begun to think that my companion was as friendless a man as I was myself.Presently, however, I found that he had many acquaintances, and those in the most different classes of society. There was one little pale rat-faced,dark eyed fellow who was introduced to me as Mr. Lestrade, and who came three or four times in a single week. One morning a young girl called, fashionably dressed, and stayed for half an hour or more-closely followed by an elderly woman in dirty clothes. On another occasion an old white-haired gendeman had an interview with my companion, and another time, a railway porter in his uniform.
At such times Sherlock Holmes used to beg for the use of the sitting-room, and I would go back to my bed-room. He always apologized to me for purting me to this inconvenience. “I have to use this room as a place of business, he said, “and these people are my clients. Again I had an opportunity of asking him a point-blank question, and again my delicacy prevented me from forcing another man to confide in me.
……

CHAPTER 1 Mr.Sherlock Holmes
CHAPTER 2 The Science of Deduction
CHAPTER 3 The Lauriston Garden Mystery
CHAPTER 4 Whatjohn Rance Had toTell
CHAPTER 5 Our Advertisement Bringsa Visitor
CHAPTER 6 Tobias Gregson Shows What He Can Do
CHAPTER 7 Lightin the Darkness
CHAPTER 8 The Flower of Utah
CHAPTER 9 A Flight for Life
CHAPTER 10 A Continuation of the Reminiscences of John Watson, M.D.
CHAPTER 11 The Conclusion