CIRCULATION OF THE BLOOD 93 



giving it motion locally, and distributing it to the body, adds 

 anything else to it heat, spirit, perfection, must be inquir- 

 ed into by-and-by, and decided upon other grounds. So 

 much may suffice at this time, when it is shown that by the 

 action of the heart the blood is transfused through the ven- 

 tricles from the veins to the arteries, and distributed by 

 them to all parts of the body. 



The above, indeed, is admitted by all, both from the struc- 

 ture of the heart and the arrangement and action of its 

 valves. But still they are like persons purblind or groping 

 about in the dark, for they give utterance to various, con- 

 tradictory, and incoherent sentiments, delivering many 

 things upon conjecture, as we have already shown. 



The grand cause of doubt and error in this subject appears 

 to me to have been the intimate connexion between the 

 heart and the lungs. When men saw both the pulmonary 

 artery and the pulmonary veins losing themselves in the 

 lungs, of course it became a puzzle to them to know how or 

 by what means the right ventricle should distribute the blood 

 to the body, or the left draw it from the venae cavse. This fact 

 is borne witness to by Galen, whose words, when writing 

 against Erasistratus in regard to the origin and use of the 

 veins and the coction of the blood, are the following 1 : "You 

 will reply," he says, "that the effect is so; that the blood 

 is prepared in the liver, and is thence transferred to the 

 heart to receive its proper form and last perfection; a state- 

 ment which does not appear devoid of reason; for no great 

 and perfect work is ever accomplished at a single effort, or 

 receives its final polish from one instrument. But if this 

 be actually so, then show us another vessel which draws the 

 absolutely perfect blood from the heart, and distributes it as 

 the arteries do the spirits over the whole body." Here then 

 is a reasonable opinion not allowed, because, forsooth, be- 

 sides not seeing the true means of transit, he could not dis- 

 cover the vessel which should transmit the blood from the 

 heart to the body at large ! 



But had anyone been there in behalf of Erasistratus, and 

 of that opinion which we now espouse, and which Galen him- 

 self acknowledges in other respects consonant with reason, to 



De PUcitis HippocratU et Platonis. H 



