Sherlock Holmes - Deductions

“From South Africa, sir, I perceive.”
“Yes, sir,” he answered, with some surprise.
“Imperial Yeomanry, I fancy.”
“Exactly.”
“Middlesex Corps, no doubt.”
“That is so. Mr. Holmes, you are a wizard.”
I smiled at his bewildered expression.
“When a gentleman of virile appearance enters my room with such tan upon his face as an English sun could never give, and with his handkerchief in his sleeve instead of in his pocket, it is not difficult to place him. You wear a short beard, which shows that you were not a regular. You have the cut of a riding-man. As to Middlesex, your card has already shown me that you are a stockbroker from Throgmorton Street. What other regiment would you join?”
“ What has been happening at Tuxbury Old Park?”
“Mr. Holmes —!”
“My dear sir, there is no mystery. Your letter came with that heading, and as you fixed this appointment in very pressing terms it was clear that something sudden and important had occurred.”

“As it was first presented to me, there were three possible explanations of the seclusion or incarceration of this gentleman in an outhouse of his father’s mansion. There was the explanation that he was in hiding for a crime, or that he was mad and that they wished to avoid an asylum, or that he had some disease which caused his segregation. I could think of no other adequate solutions.”

“The criminal solution would not bear inspection. No unsolved crime had been reported from that district. I was sure of that. If it were some crime not yet discovered, then clearly it would be to the interest of the family to get rid of the delinquent and send him abroad rather than keep him concealed at home.”

“Insanity was more plausible. The presence of the second person in the outhouse suggested a keeper. The fact that he locked the door when he came out strengthened the supposition and gave the idea of constraint. On the other hand, this constraint could not be severe or the young man could not have got loose and come down to have a look at his friend. You will remember, Mr. Dodd, that I felt round for points, asking you, for example, about the paper which Mr. Kent was reading. Had it been the Lancet or the British Medical Journal it would have helped me.”

“There remained the third possibility, into which, rare and unlikely as it was, everything seemed to fit. Leprosy is not uncommon in South Africa. By some extraordinary chance this youth might have contracted it. His people would be placed in a very dreadful position, since they would desire to save him from segregation. Great secrecy would be needed to prevent rumours from getting about and subsequent interference by the authorities. A devoted medical man, if sufficiently paid, would easily be found to take charge of the sufferer. There would be no reason why the latter should not be allowed freedom after dark. Bleaching of the skin is a common result of the disease. The case was a strong one — so strong that I determined to act as if it were actually proved. When on arriving here I noticed that Ralph, who carries out the meals, had gloves which are impregnated with disinfectants, my last doubts were removed.”