With these words Jacobus de Back reported the confusion in the schools at the collapse of traditional natural philosophy. He had taken his MD in Franeker in 1616, when medicine and natural philosophy were still sisters, as they had been throughout the Latin tradition. But by the 1630s not only were philosophers seeing a battle between Aristotelianism and the mechanical philosophy, but within medicine some of the major doctrines of Hippocrates and Galen had been shown to be wrong. De Back felt the pull of old loyalties and declared that he still belonged to the ancient physicians; but clearly they were going to need another re-evaluation to show that they still had authority in a changed society.

How had this crisis come about? Rather than retell a traditional story of a revolution in natural philosophy, let us look at its relation to medicine from the point of view of the Rational and Learned Doctor, who still wanted to be successful.

EPIDEMICS CHANGE MEDICINE

The two great epidemics, the plague and the French Disease, left marks on European medicine. While the Learned and Rational Doctors struggled to get to grips with these new and unknown, or at least improperly labelled diseases, laymen took practical measures such as quarantine and isolation of the affected, and built hospitals to contain them.