THE GROWTH OF TRUTH 19 



absolutely in all conceptions of the functions of the 

 body, and in no department more serenely than in that 

 relating to the heart, the blood and its movements. 

 Upon his views I need not dwell further than to remind 

 you that he regarded the liver as the source of the 

 blood, of which there were two kinds, the one in the 

 veins, the other in the arteries, both kinds in ceaseless 

 ebb and flow, the only communication between these 

 closed systems being through pores in the ventricular 

 septum. He knew the lesser circulation, but thought 

 it only for the nutrition of the lungs. The heart was 

 a lamp which is furnished with oil by the blood and 

 with air from the lungs. Practically until the middle of 

 the seventeenth century Galen's physiology ruled the 

 schools, and yet for years the profession had been in 

 latent possession of a knowledge of the circulation. 

 Indeed, a good case has been made out for Hippocrates, 

 in whose works occur some remarkably suggestive sen- 

 tences. 1 In the sixteenth century the lesser circulation 

 was described with admirable fullness by Servetus and 

 by Columbus, and both Sarpi and Caesalpinus had 

 Hippocratic glimmerings of the greater circulation. 

 These men, with others doubtless, were in latent posses- 

 sion of the truth. But every one of them saw darkly 

 through Galenical glasses, and theirs was the hard but 

 the common lot never to reach such conscious posses- 

 sion as everywhere to make men acquiesce. One must 

 have the disinterestedness of the dead to deal with 

 a problem about which controversy has raged, and in 

 which national issues have been allowed to blur the 

 brightness of an image which would be clear as day to 

 those with eyes to see. Nor would I refer to a matter 

 long since settled by those best competent to judge, had 

 1 Willis's Harvey, pp. 21-2. 



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