The Turk and the Futurists by G.K. Chesterton

MR. ADRIAN CROOKE was a successful chemist whose shop was in the neighbourhood of Victoria, but his face expressed more than is generally required in a successful chemist. It was a curious face, prematurely old and like parchment, but acute and decisive, with real headwork in every line of it. Nor was his conversation, when he did converse, out of keeping with this: he had lived in many countries, and had a rich store of anecdote about the more quaint and sometimes the more sinister side of his work, visions of the vapour of eastern drugs or guesses at the ingredients of Renascence poisons. He himself, it need hardly be said, was a most respectable and reliable apothecary, or he would not have had the custom of families, especially among the upper classes; but he enjoyed as a hobby, the study of the dark days and lands where his science had lain sometimes on the borders of magic and sometimes upon the borders of murder.

Hence it often happened that persons, who in their serious senses were well aware of his harmless and useful habits, would leave his shop on some murky and foggy night, with their heads so full of wild tales of the eating of hemp or the poisoning of roses, they could hardly help fancying that the shop, with its glowing moon of crimson or saffron, like bowls of blood and sulphur, was really a house of the Black Art.