Put off your imagination, as you put off your overcoat, when you enter the laboratory. Put it on again, as you put on your overcoat, when you leave.

He firmly believed that the advancement of medicine and the relief of human suffering justified the suffering of animals but his wife was not convinced. ” In fact a “very frequent application of mathematics to biology [is] the use of averages”—that is statistics—which may give only “apparent accuracy. "


Introduction to the Study of Experimental Medicine
In his major discourse on scientific method An Introduction to the Study of Experimental Medicine (1865) Claude Bernard describes what makes a scientific theory good and what makes a scientist important a true discoverer.

Bernard Cohen of Harvard University called Bernard "one of the greatest of all men of science". Historian of science I.