There was something that touched me as I read this letter, something pitiable in the reiterated appeals to bring Holmes. So moved was I that even had it been a difficult matter I should have tried it, but of course I knew well that Holmes loved his art, so that he was ever as ready to bring his aid as his client could be to receive it. My wife agreed with me that not a moment should be lost in laying the matter before him, and so within an hour of breakfast-time I found myself back once more in the old rooms in Baker Street. Holmes was seated at his side-table clad in his dressing-gown, and working hard over a chemical investigation. A large curved retort was boiling furiously in the bluish flame of a Bunsen burner, and the distilled drops were condensing into a two-litre measure. My friend hardly glanced up as I entered, and I, seeing that his investigation must be of importance, seated myself in an armchair and waited. He dipped into this bottle or that, drawing out a few drops of each with his glass pipette, and finally brought a test-tube containing a solution over to the table. In his right hand he held a slip of litmus-paper. “You come at a crisis, Watson,” said he. “If this paper remains blue, all is well. If it turns red, it means a man’s life.” He dipped it into the test-tube and it flushed at once into a dull, dirty crimson. “Hum! I thought as much!” he cried. “I will be at your service in an instant, Watson. You will find tobacco in the Persian slipper.” He turned to his desk and scribbled off several telegrams, which were handed over to the page-boy. Then he threw himself down into the chair opposite, and drew up his knees until his fingers clasped round his long, thin shins. “A very commonplace little murder,” said he. “You’ve got something better, I fancy. You are the stormy petrel of crime, Watson. What is it?” I handed him the letter, which he read with the most concentrated attention. “It does not tell us very much, does it?” he remarked, as he handed it back to me. “Hardly anything.” “And yet the writing is of interest.” “But the writing is not his own.” “Precisely. It is a woman’s.” “A man’s surely,” I cried. “No, a woman’s, and a woman of rare character. You see, at the commencement of an investigation it is something to know that your client is in close contact with some one who, for good or evil, has an exceptional nature. My interest is already awakened in the case. If you are ready we will start at once for Woking, and see this diplomatist who is in such evil case, and the lady to whom he dictates his letters.”