THE iilRTH AKD GROWTH 0¥ SCIENCE H\ MEDICINE, y 



they felt sure must govern Nature. Their great contri- 

 bution to science was to establish that atmosphere of 

 intellectual liberty which rendered science possible. It 

 says much for the liberal spirit of that age that these 

 men, who broke with all the cherished traditions of the 

 past, were not, as a rule, reviled for impiety, but received 

 universal honour. Thales was accounted one of the 

 seven wise men of Greece. 



It is easy for us to smile at the crudity of some of the 

 attempts of these early philosophers to explain Nature. 

 Yet they early recognised the permanence and inde- 

 structibility of matter, and one of their chief preoccupations 

 was the search after the primary substance out of which 

 they conceived everything to arise. Some identified it 

 with water, some with air, and Empedocles, in the fifth 

 century B.C. is credited with formulating the doctrine of 

 the four elements, earth, air, fire and water, which was 

 to dominate scientific thought for more than a thousand 

 years. The obvious antagonism between heat and cold, 

 dryness and moisture, early led to the doctrine of 

 " opposites," which became one of the chief tenets of 

 Greek medicine. Even the atomic theory can be traced 

 back to Leucippus of Miletus in the fifth century B.C. 

 This conception, elaborated some four centuries later in 

 the well-known poem of Lucretius, is an interesting 

 example of a hypothesis reached by sheer thinking, but 

 remaining sterile for 2000 j-ears, till established by the 

 experimental method in the hands of Dalton. That 

 marks the difference between the science of the armchair 

 and that of the laboratory. 



But let me now consider what the earlier Greeks did 

 for medical science. Medicine of a sort and rude surgery 

 must have been transmitted even through the dark ages, 

 handed down, it is said, by special families — the Askle- 

 piadae — just as the epic tradition was passed along by the 

 Homendge. Certain rules of surgery and the practices of 

 blood-letting and purgation are known to be of immemorial 

 antiquity, but for the most part the medical practice of 



