CHAPTER VII 



THE BLOOD PERCOLATES THE SUBSTANCE OF THE 

 LUNGS FROM THE RIGHT VENTRICLE OF THE HEART 

 INTO THE PULMONARY VEINS AND LEFT VENTRICLE 



THAT this is possible, and that there is nothing to 

 prevent it from being so, appears when we reflect on 

 the way in which water percolating the earth produces 

 springs and rivulets, or when we speculate on the 

 means by which the sweat passes through the skin, 

 or the urine through the parenchyma of the kidneys. 

 It is well known that persons who use the Spa waters, 

 or those of La Madonna, in the territories of Padua, or 

 others of an acidulous or vitriolated nature, or who 

 simply swallow drinks by the gallon, pass all off again 

 within an hour or two by urine. Such a quantity of 

 liquid must take some short time in the concoction : 

 it must pass through the liver ; (it is allowed by all 

 that the juices of the food we consume pass twice 

 through this organ in the course of the day ;) it must 

 flow through the veins, through the parenchyma of the 

 kidneys, and through the ureters into the bladder. 



To those, therefore, whom I hear denying that the 

 blood, aye the whole mass of the blood may pass 

 through the substance of the lungs, even as the 

 nutritive juices percolate the liver, asserting such a 

 proposition to be impossible, and by no means to be 

 entertained as credible, I reply, with the poet, that 

 they are of that race of men who, when they will r 

 assent full readily, and when they will not, by no- 

 manner of means ; who, when their assent is wanted, 

 fear, and when it is not, fear not to give it. 



49 E 



