The history of medicine and surgery during the Middle Ages has been greatly obscured by the assumption that at this time scientific medicine and surgery could scarcely have developed because men were lacking in the true spirit of science. The distinction between modern and medieval education is often said to be that the old-time universities sought to increase knowledge by deduction, while the modern universities depend on induction. Inductive science is often said to be the invention of the Renaissance period, and to have had practically no existence during the Middle Ages. The medieval scholars are commonly declared to have preferred to appeal to authority, while modern investigators turn to experience. Respect for authority is often said to have gone so far in the Middle Ages that no one ventured practically to assert anything unless he could find some authority for it. On the other hand, if there was any acknowledged authority, say Aristotle or Galen, men so hesitated to contradict him that they usually followed one another like sheep, quoting their favourite author and swearing by the authority of their chosen master. Indeed, many modern writers have not hesitated to express the greatest possible wonder that the men of the Middle Ages did not think more for themselves, and above all did not trust to their own observation, rather than constantly rest under the shadow of authority. Above all, it is often asked why there was no nature study in the Middle Ages--that is, why men did not look around them and see the beauties and the wonders of the world and of nature, and becoming interested in them, endeavour to learn as much as possible about them. Anyone who thinks that there was no nature study in the Middle Ages, however, is quite ignorant of the books of the Middle Ages. Dante, for instance, is full of the knowledge of nature. What he knows about the ants, and the bees, and many other insects; about the flowers, and the birds, and the habits of animals; about the phosphorescence at sea and the cloud effects, and nearly everything else in the world of nature around him, adds greatly to the interest of his poems. He uses all these details of information as figures in his "Divine Comedy," not in order to display his erudition, but to bring home his meaning with striking concreteness by the metaphors which he employs. There is probably no poet in the modern time who knows more about the science of his time than Dante, or uses it to better advantage.