“Some experts… believed that injected morphine was not addictive, though it was when taken orally. One North Carolina doctor told [researcher H.H.] Kane in 1880 in perfect innocence: ‘On one patient I have used the hypodermic needle between 2,500 and 3,000 times in a period of 18 months, and so far I see no signs of the opium habit.’ He obviously arrived with his needle before the onset of withdrawal symptoms.”
— From “Drugs in America: A Social History, 1800-1980” by H. Wayne Morgan (1981)