SEVENTEENTH AND EIGHTEENTH CENTURIES 175 



more idealistic; in the former case one was bewildered, since mechanics can- 

 not provide the answer to more than a small fraction of the questions which 

 the new discovery brought to light; while in the latter case there was the 

 risk of reverting to mysticism in one form or another. These natural-scientific 

 speculations from the beginning of the eighteenth century, which we shall 

 now discuss, originated, curiously enough, less from the anatomists and 

 biologists than from the medical practitioners, who sought to base their 

 medical treatment on a general theory of the functions of the body. Of these 

 latter scientists some few have exercised a radical influence even on the gen- 

 eral development of biology and therefore deserve to be mentioned in this 

 connexion. 



Thomas Sydenham lived, it is true, entirely in the seventeenth century — 

 he was born in 162.4 ^^'^ ^^^'^ ^^ ^^^9 — ^^^ ^^^ influence did not really make 

 itself felt until after his death, and, indeed, it has increased still more since 

 then. He belonged to a good country-family and studied for a time at Oxford, 

 but upon the outbreak of the Civil War he joined the Parliamentary party 

 and became an officer in its army. Afterwards, however, he continued his 

 medical studies, took a low medical degree, and settled down in London as 

 a pracititoner; he did not obtain his doctor's degree until he was over fifty 

 years old. Personally Sydenham enjoyed a great reputation; he counted among 

 his friends such people as the chemist Boyle and the philosopher Locke. On 

 the other hand, opinions differed as to his capacity as a physician; his auda- 

 cious ideas required time before they could penetrate the ordinary mind. 

 Nowadays he is universally regarded as one of the pioneers of medical 

 science. 



Sydenham s medical doctrine 

 In the seventeenth century London was a very unhealthful city; one plague 

 followed another in rapid succession. It was these epidemics that inspired 

 Sydenham to work out his medical theories; he studied the symptoms of 

 the various diseases and endeavoured by that means to characterize the dis- 

 ease itself in the same way as the botanist describes a plant-species. "That 

 botanist would have but little conscience who contented himself with the 

 general description of a thistle and overlooked the special and peculiar char- 

 acteristics in each species." He places a higher value on this exact study of 

 nature than on any theories; this study should take into account all factors 

 affecting the disease in its entirety. Even the season of the year when the dis- 

 ease is most widely dispersed should be carefully observed, as indeed all other 

 conditions that may influence the plague as a whole. On the other hand, 

 purely individual variations in particular cases are of minor interest. Like 

 Hippocrates he considers that it is the nature of the patient that cures dis- 

 ease; it is therefore not so much worth while worrying about trying to 

 diagnose the disorders in the fluids of the body on each occasion as to try to 



