CHAPTER III 



WILLIAM HARVEY AND EXPERIMENTAL OBSERVA- 



TION 



After the splendid observations of Vesalius, revealing in 

 a new light the construction of the human body. Harvey took 

 the next general step by introducing experiment to determine 

 the use or purpose of the structures that Vesalius had so 

 clearly exposed. Thus the work of Harvey was complemental 

 to that of Vesalius, and we may safely say that, taken together, 

 the work of these two men laid the foundations of the modern 

 method of investigating nature. The results they obtained, 

 and the influence of their method, are of especial interest to us 

 in the present connection, inasmuch as they stand at the 

 beginning of biological science after the Renaissance. Al- 

 though the observations of both were applied mainly to the 

 human body, they served to open the entire field of structural 

 studies and of experimental observations on living organisms. 



Many of the experiments of Harvey, notably those relating 

 to the movements of the heart, were, of course, conducted 

 upon the lower animals, as the frog, the dog, etc. His ex- 

 periments on the living human body consisted mainly in 

 applying ligatures to the arms and the legs. Nevertheless, 

 the results of all his experiments related to the phenomena of 

 the circulation in the human body, and were primarily for 

 the use of medical men. 



In what sense the observations of the two men were com- 

 plemental will be better understood when we remember that 

 there are two aspects in which living organisms should 

 always be considered in biological studies; first, the struc- 



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