Read the given passage and answer the questions.
“You interest me very much, Mr Holmes. I had hardly expected so long a skull or such well marked frontal head. A cast of your skull, sir, until the original is available, would be an ornament to any anthropological museum. It is not my intention to be fulsome, but I confess that I covet your skull,” said the strange visitor. Sherlock Holmes waved the visitor into a chair. “You are an enthusiast in your line of thought, I perceive, sir, as I am in mine,” said he. “I observe from your forefinger that you make your own cigarettes. Have no hesitation in lighting one.” The man drew out paper and tobacco and twirled the one up in the other with surprising dexterity. He had long, quivering fingers as agile and restless as the antennae of an insect. Holmes was silent, but his little darting glances showed me the interest which he took in our curious companion. “I presume, sir,” said he at last, “that it was not merely for the purpose of examining my skull that you have done me the honour to call here last night and again today?” “No, sir, no; though I am happy to have had the opportunity of doing that as well. I came to you, Mr Holmes because I recognised that I am myself an unpractical man and because I am suddenly confronted with a most serious and extraordinary problem. Recognising, as I do, that you are the second highest expert in Europe—” “Indeed, sir! May I inquire who has the honour to be the first?” asked Holmes with some asperity. “To the man of precisely scientific mind, the work of Monsieur Bertillon must always appeal strongly.” “Then had you not better consult him?” “I said, sir, to the precisely scientific mind. But as a practical man of affairs, it is acknowledged that you stand alone. I trust, sir, that I have not inadvertently—” “Just a little,” said Holmes. “I think, Dr Mortimer, you would do wisely if without more ado you would kindly tell me plainly what the exact nature of the problem is in which you demand my assistance.”
The purpose of the stranger’s visit is: