1 76 Letters 



by the arteries to the general system, and returning 

 from this by the veins back to the heart, and with such 

 an ebb and flow, in such mass and quantity that it 

 must necessarily move in some way in a circuit. But 

 if you will be kind enough to refer to my eighth and 

 ninth chapters you will find it stated in so many words 

 that I have purposely omitted to speak of the concoction 

 of the blood, and of the causes of this motion and 

 circulation, especially of the final cause. So much I 

 have been anxious to say, that I might purge myself in 

 the eyes of a learned and much respected man, that I 

 might feel absolved of the infamy of meriting such 

 censure. And I beg you to observe, my learned, my 

 impartial friend, if you would see with your own eyes 

 the things I affirm in respect of the circulation, and 

 this is the course which most beseems an anatomist, 

 that I engage to comply with your wishes, whenever a 

 fit opportunity is afforded ; but if you either decline 

 this, or care not by dissection to investigate the subject 

 for yourself, let me beseech you, I say, not to vilipend 

 the industry of others, nor charge it to them as a 

 crime ; do not derogate from the faith of an honest 

 man, not altogether foolish nor insane, who has had 

 experience in such matters for a long series of years. 



Farewell, and beware ! and act by me, as I have done 

 by you ; for what you have written I receive as uttered 

 in all candour and kindness. Be sure, in writing to 

 me in return, that you are animated by the same 

 sentiments. 



Nurnberg, May 2Oth, 1636. 



LETTER II 

 To Paul Marquard Slegel, of Hamburg 



I congratulate you much, most learned sir, on your 

 excellent commentary, in which you have replied in a 

 very admirable manner to Riolanus, the distinguished 



