“There is danger for him who taketh the tiger cub, and danger also for whoso snatches a delusion from a woman.”

“They're dangerous at both ends...and crafty in the middle.”

“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.”

“It is stupidity rather than courage to refuse to recognize danger when it is close upon you.”

“Evil indeed is the man who has not one woman to mourn him.”

“There is a danger there - a very real danger to humanity. Consider, Watson, that the material, the sensual, the worldly would all prolong their worthless lives. The spiritual would not avoid the call to something higher. It would be the survival of the least fit. What sort of cesspool may not our poor world become?”

“His incredible untidiness, his addiction to music at strange hours, his occasional revolver practice within doors, his weird and often malodorous scientific experiments, and the atmosphere of violence and danger which hung around him made him the very worst tenant in London.”