This clip from the 1935 film The Story of Louis Pasteur features a scene of professor Pasteur speaking to students at the university where he says:
You young men, doctors and scientists of the future, do not let yourselves be tainted by apparent skepticism. Nor discouraged by the sadness of certain hours that creep over nations. Do not become angry at your opponents. For no scientific theory has ever been accepted without opposition. Live in the serene peace of libraries and laboratories. Say to yourselves first, “What have I done for my instruction?” And as you gradually advance, “What am I accomplishing,” until the time comes when you may have the immmense happiness of thinking that you have contributed in some way to the welfare and progress of mankind.