596 LETTERS.
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, when- ever 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 in- dustry 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 20th, 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 Biolanus, the distinguished anatomist, and, as you say, formerly your teacher : invincible truth has, indeed, taught the scholar to vanquish the master. I was myself preparing a sponge for his most recent arguments ; but intent upon my work ' On the Generation of Animals' (which, but just
�� �
