LETTERS. 597 



come forth, I send to you), I have not had leisure to produce it. 

 And now I rather rejoice in the silence, as from your supple- 

 ment I perceive that it has led you to come forward with your 

 excellent reflections, to the common advantage of the world of 

 letters. For I see that in your most ornate book (I speak 

 without flattery), you have skilfully ' and nervously confuted 

 all his machinations against the circulation, and successfully 

 thrown down the scaffolding of his more recent opinions. I 

 am, therefore, but little solicitous about labouring at any 

 ulterior answer. Many things might, indeed, be adduced in 

 confirmation of the truth, and several calculated to shed clearer 

 light on the art of medicine ; but of these we shall perhaps 

 see further by and by. 



Meantime, as Riolanus uses his utmost efforts to oppose the 

 passage of the blood into the left ventricle through the lungs, 

 and brings it all hither through the septum, and so vaunts 

 himself on having upset the very foundations of the Harveian 

 circulation (although I have nowhere assumed such a basis 

 for my doctrine; for there is a circulation in many red-blooded 

 animals that have no lungs), it may be well here to relate an 

 experiment which I lately tried in the presence of several of 

 my colleagues, and from the cogency of which there is no 

 means of escape for him. Having tied the pulmonary artery, 

 the pulmonary veins, and the aorta, in the body of a man 

 who had been hanged, and then opened the left ventricle of 

 the heart, we passed a tube through the vena cava into the 

 right ventricle of the heart, and having, at the same time, 

 attached an ox's bladder to the tube, in the same way as a 

 clyster-bag is usually made., we filled it nearly full of warm 

 water, and forcibly injected the fluid into the heart, so that 

 the greater part of a pound of water was thrown into the 

 right auricle and ventricle. The result was, that the right 

 ventricle and auricle were enormously distended, but not a 

 drop of water or of blood made its escape through the orifice 

 in the left ventricle. The ligatures having been undone, the 

 same tube was passed into the pulmonary artery, and a tight 

 ligature having been put round it to prevent any reflux into 

 the right ventricle, the water in the bladder was now pushed 

 towards the lungs, upon which a torrent of the fluid, mixed 

 with a quantity of blood, immediately gushed forth from the 



