I am, by calling, a dealer in words; and words are, of course, the most powerful drug used by mankind. Not only do words infect, ergotise, narcotise, and paralyse, but they enter into and colour the minutest cells of the brain, very much as madder mixed with a stag’s food at the Zoo colours the growth of the animal’s antlers. Moreover, in the case of the human animal, that acquired tint, or taint, is transmissible.

from Rudyard Kipling’s Book of Words, in the chapter titled Surgeons and the Soul. I came across a version of the quote in bold above, in a fascinating and insightful documentary about, not writing or literature, but healthy eating and living called Hungry for Change. The quote is used to highlight the power of words in influencing one’s behavior and state of mind.