A dog reflects the family life. Whoever saw a frisky dog in a gloomy family, or a sad dog in a happy one? Snarling people have snarling dogs, dangerous people have dangerous ones.

I could not rest, Watson, I could not sit quiet in my chair, if I thought that such a man as Professor Moriarty were walking the streets of London unchallenged.

'Men die of the diseases which they have studied most,' remarked the surgeon, snipping off the end of a cigar with all his professional neatness and finish. 'It's as if the morbid condition was an evil creature which, when it found itself closely hunted, flew at the throat of its pursuer. If you worry the microbes too much they may worry you. I've seen cases of it, and not necessarily in microbic diseases either. There was, of course, the well-known instance of Liston and the aneurism; and a dozen others that I could mention.'

It is a fool's plan to teach a man to be a cur in peace, and think that he will be a lion in war.

‎A change of work is the best rest.

'There's no need for fiction in medicine,' remarks Foster... 'for the facts will always beat anything you fancy.'

He seems to have declared war on the King’s English as well as on the English king.