THE ORGANS OF VOLUNTARY MOTION. 433 



the Europeans of the dark ages, the writings of 

 Galen had almost unquestioned authority 18 ; and it 

 was only by an uncommon effort of independent 

 thinking that Abdollatif ventured to assert, that even 

 Galen's assertions must give way to the evidence of 

 the senses. In more modern times, when Vesalius, 

 in the sixteenth century, accused Galen of mistakes, 

 he drew upon himself the hostility of the whole 

 body of physicians. Yet the mistakes were such as 

 might have been pointed out and confessed 19 with- 

 out acrimony, if, in times of revolution, mildness 

 and moderation were possible; but an impatience 

 of the superstition of tradition on the part of the 

 innovators, and an alarm of the subversion of all 

 recognized truths on the part of the established 

 teachers, inflame and pervert all such discussions. 

 Vesalius's main charge against Galen is, that his 

 dissections were performed upon animals, and not 

 upon the human body. Galen himself speaks of the 

 dissection of apes as a very familiar employment, 

 and states that he killed them by drowning. The 

 natural difficulties which, in various ages, have pre- 

 vented the unlimited prosecution of human dissec- 

 tion, operated strongly among the ancients, and it 

 would have been difficult, under such circumstances, 

 to proceed more judiciously than Galen did. 



I shall now proceed to the history of the disco- 

 very of another and less obvious function, the circu- 

 lation of the blood, which belongs to modern times. 

 18 Sprengel, ii. 359. 19 Cuv. Le? ons sur I' Hist, des Sc. Nat. p. 25. 

 VOL. III. F F 



