396 INTRODUCTORY LECTURES. 



Chemistry now prevailed, and the authority of Aristotle in 

 philosophy, and that of Galen in physic, were destroyed, or 

 very much weakened ; and, in general, men were prepared for 

 new opinions, when Dr. Harvey, by publishing his doctrine of 

 the circulation of the blood, finished the ruin of the whole 

 Galenic fabric, and at the same time made way for the correc- 

 tion of the chemical system, or at least obviated the bias that 

 then ran too strong in its favour. 



For a hundred years before Dr. Harvey, anatomists had been 

 daily improving in the knowledge of the human body, but they 

 had not yet acquired any proper or just view of the connexion 

 of the whole, and therefore were not in a condition to reason pro- 

 perly concerning its functions. The chemists hardly contri- 

 buted to any improvement in this respect ; they only afforded a 

 different language with regard to the different states of the 

 fluids. It was the knowledge of the circulation of the blood, 

 which had been aimed at by several physicians before but only 

 completed by Dr Harvey, that gave some view of the con- 

 nexion of the whole system. About six years before the publi- 

 cation of Dr. Harvey's work, Asellius had discovered the 

 Lacteals; and about the time that the doctrine of the circulation 

 came to be generally received in Europe, (1650) Pecquet had 

 discovered the receptacle of the chyle and thoracic duct, so that, 

 the true course of the blood and of the chyle being now known, 

 it was very properly observed by Gassendi, that it was upon 

 these two poles that the system of physic must afterwards turn. 

 They had immediately the effect of removing the liver from 

 the important function it had held so long in the system of 

 Galen. 



It was to be expected, that the discovery of the circula- 

 tion of the blood would have considerable effects on the sys- 

 tem of physic, which must be always correct and complete 

 in proportion to our knowledge of the structure and me- 

 chanism of the human body. Hitherto the anatomists had 

 laboured, as we may say, only on the detached and separate 

 parts of the economy, without perceiving the connexion of the 

 whole, or, what was worse, they had the false view which Galen 

 had given of it. It was the discovery of the circulation of the 

 blood, and of the course of the chyle, that first gave the pro- 



