A SECOND DISQUISITION TO JOHN RIOLAN. 



IT is now many years, most learned Riolanus, since, with 

 the aid of the press, I published a portion of my work. But 

 scarce a day, scarce an hour, has passed since the birth-day of 

 the Circulation of the blood, that I have not heard something 

 for good or for evil said of this my discovery. Some abuse it 

 as a feeble infant, and yet unworthy to have seen the light ; 

 others, again, think the bantling deserves to be cherished and 

 cared for ; these oppose it with much ado, those patronize it with 

 abundant commendation; one party holds that I have com- 

 pletely demonstrated the circulation of the blood by experiment, 

 observation, and ocular inspection, against all force and array of 

 argument ; another thinks it scarcely yet sufficiently illustrated 

 not yet cleared of all objections. There are some, too, who 

 say that I have shown a vainglorious love of vivisections, and 

 who scoff at and deride the introduction of frogs and serpents, 

 flies, and others of the lower animals upon the scene, as a piece 

 of puerile levity, not even refraining from opprobrious epithets. 



To return evil speaking with evil speaking, however, I hold 

 to be unworthy in a philosopher and searcher after truth ; I 

 believe that I shall do better and more advisedly if I meet so 

 many indications of ill breeding with the light of faithful and 

 conclusive observation. It cannot be helped that dogs bark 

 and vomit their foul stomachs, or that cynics should be num- 

 bered among philosophers ; but care can be taken that they do 

 not bite or inoculate their mad humours, or with their dogs' 

 teeth gnaw the bones and foundations of truth. 



Detractors, mummers, and writers denied with abuse, as I 

 resolved with myself never to read them, satisfied that nothing 



