756 THE HARVEIAN ORATION. 



muscular character, and so much else, was already to be found in 

 the writings or teachings of his predecessors ? To all this we can 

 answer, as indeed, it seems probable, was practically answered even 

 within Harvey's lifetime, what was left for Harvey to discover was 

 nothing less than the circulation itself. His predecessors had but 

 impinged, and that by guesswork, upon different segments of the 

 circle, and then gone off at a tangent into outer darkness, whilst he 

 worked and proved and demonstrated round its entire periphery. 

 His demonstrations and direct proofs were all new, and his indirect 

 arguments nearly all new. Whenever he made use of anything 

 already known, he most punctually acknowledged it. Of his de- 

 monstration in the way of injection I have already spoken ; of his 

 demonstration of the use of the valves in the veins, and his proof 

 that they are similar in function to the arterial, a fact previously 

 unsuspected (see p. 6^, Ic.), the thirteenth chapter of the treatise 

 ' De Motu ' speaks with figures ; of his indirect, but irrefragable 

 argument, in the eighth chapter, from the quantity of blood thrown 

 out by the heart at each pulsation, an argument which a mathe- 

 matician such as Harriott, or Warner, might have hit upon, but, so 

 far as I have found, did not, he speaks himself as being 'adeo 

 novum et inauditum ut verear ne habeam inimicos omnes homines ; ' 

 and finally, the argument, which though it be indirect, every 

 morphologist will allow to be not only most exquisite, but also most 

 convincing, for the circulation in the adult warm-blooded animal, 

 drawn from the relations held by the venae cavae to the efferent 

 arteries in the embryo, and in all animals with but a single or an 

 imperfectly divided ventricle, ' unus duntaxat ventriculus vel quasi 

 unus,' and of which I would recommend every one who is not 

 already acquainted with it, to gain a knowledge from the seventh 

 chapter of the same book, was his, and his alone. With regard to 

 all these points, with regard, that is, to the circulation as a whole ; 

 with regard to the actual demonstration and exhibition of it as 

 opposed to mere guessing about it ; with regard to all, or nearly 

 all, sound reasoning as to any large portion of it, Harvey might 

 have said with Lucretius, 



*Avia Pieridum peragro loca nuUius ante 

 Trita solo'; 



or in the words of a poet of another country, and a later age, 



*We were the first that ever burst 

 Into that silent sea.' 



