On The Natural Faculties
*i.e. the tissues.
"My good sir, do not run us down in this rhetorical fashion without some proof; state some definite objection to our view, in order that either you may convince us by a brilliant refutation of the ancient doctrine, or that, on the other hand, we may convert you from your ignorance." Yet why do I say "rhetorical"? For we too are not to suppose that when certain rhetoricians pour ridicule upon that which they are quite incapable of refuting, without any attempt at argument, their words are really thereby constituted rhetoric. For rhetoric proceeds by persuasive reasoning; words without reasoning are buffoonery rather than rhetoric. Therefore, the reply of Erasistratus in his treatise "On Deglutition" was neither rhetoric nor logic. For what is it that he says? "Now, the stomach does not appear to exercise any traction." Let us testify against him in return, and set our argument beside his in the same form. Now, there appears to be no peristalsis of the gullet. "And how does this appear?" one of his adherents may perchance ask. "For is it not indicative of peristalsis that always when the upper parts of the gullet contract the lower parts dilate?" Again, then, we say, "And in what way does the attraction of the stomach not appear? For is it not indicative of attraction that always when the lower parts of the gullet dilate the upper parts contract?" Now, if he would but be sensible and recognize that this phenomenon is not more indicative of the one than of the other view, but that it applies equally to both, we should then show him without further delay the proper way to the discovery of truth.
We will, however, speak about the stomach again. And the dispersal of nutriment [anadosis] need not make us have recourse to the theory regarding the natural tendency of a vacuum to become refilled, when once we have granted the attractive faculty of the kidneys. Now, although Erasistratus knew that this faculty most certainly existed, he neither mentioned it nor denied it, nor did he make any statement as to his views on the secretion of urine.
Why did he give notice at the very beginning of his "General Principles" that he was going to speak about natural activities- firstly what they are, how they take place, and in what situations- and then, in the case of urinary secretion, declared that this took place through the kidneys, but left out its method of occurrence? It must, then, have been for no purpose that he told us how digestion occurs, or spends time upon the secretion of biliary superfluities; for in these cases also it would have been sufficient to have named the parts through which the function takes place, and to have omitted the method. On the contrary, in these cases he was able to tell us not merely through what organs, but also in what way it occurs- as he also did, I think, in the case of anadosis; for he was not satisfied with saying that this took place through the veins, but he also considered fully the method, which he held to be from the tendency of a vacuum to become refilled. Concerning the secretion of urine, however, he writes that this occurs through the kidneys, but does not add in what way it occurs. I do not think he could say that this was from the tendency of matter to fill a vacuum, for, if this were so, nobody would have ever died of retention of urine, since no more can flow into a vacuum than has run out. For, if no other factor comes into operation save only this tendency by which a vacuum becomes refilled, no more could ever flow in than had been evacuated. Nor, could he suggest any other plausible cause, such, for example, as the of nutriment by the stomach which occurs in the process of anadosis; this had been entirely disproved in the case of blood in the vena cava; it is excluded, not merely owing to the long distance, but also from the fact that the overlying heart, at each diastole, robs the vena cava by violence of a considerable quantity of blood.
In relation to the lower part of the vena cava there would still remain, solitary and abandoned, the specious theory concerning the filling of a vacuum. This, however, is deprived of plausibility by the fact that people die of retention of urine, and also, no less, by the situation of the kidneys. For, if the whole of the blood were carried to the kidneys, one might properly maintain that it all undergoes purification there. But, as a matter of fact, the whole of it does not go to them, but only so much as can be contained in the veins going to the kidneys; this portion only, therefore, will be purified. Further, the thin serous part of this will pass through the kidneys as if through a sieve, while the thick sanguineous portion remaining in the veins will obstruct the blood flowing in from behind; this will first, therefore, have to run back to the vena cava, and so to empty the veins going to the kidneys; these veins will no longer be able to conduct a second quantity of unpurified blood to the kidneys- occupied as they are by the blood which had preceded, there is no passage left. What power have we, then, which will draw back the purified blood from the kidneys? And what power,in the next place, will bid this blood retire to the lower part of the vena cava, and will enjoin on another quantity coming from above not to proceed downwards before turning off into the kidneys?
Now Erasistratus realized that all these ideas were open to many objections, and he could only find one idea which held good in all respects- namely, that of attraction. Since, therefore, he did not wish either to get into difficulties or to mention the view of Hippocrates, he deemed it better to say nothing at all as to the manner in which secretion occurs.
But even if he kept silence, I am not going to do so. For I know that if one passes over the Hippocratic view and makes some other pronouncement about the function of the kidneys, one cannot fall to make oneself utterly ridiculous. It was for this reason that Erasistratus kept silence and Asclepiades lied; they are like slaves who have had plenty to say in the early part of their career, and have managed by excessive rascality to escape many and frequent accusations, but who, later, when caught in the act of thieving, cannot find any excuse; the more modest one then keeps silence, as though thunderstruck, whilst the more shameless continues to hide the missing article beneath his arm and denies on oath that he has ever seen it. For it was in this way also that Asclepiades, when all subtle excuses had failed him and there was no longer any room for nonsense about "conveyance towards the rarefied part [of the air]," and when it was impossible without incurring the greatest derision to say that this superfluity [i.e. the urine] is generated by the kidneys as is bile by the canals in the liver- he, then, I say, clearly lied when he swore that the urine does not reach the kidneys, and maintained that it passes, in the form of vapour, straight from the region of the vena cava, to collect in the bladder.
Like slaves, then, caught in the act of stealing, these two are quite bewildered, and while the one says nothing, the other indulges in shameless lying.
17. Now such of the younger men as have dignified themselves with the names of these two authorities by taking the appellations "Erasistrateans" or "Asclepiadeans" are like the Davi and Getae- the slaves introduced by the excellent Menander into his comedies. As these slaves held that they had done nothing fine unless they had cheated their master three times, so also the men I am discussing have taken their time over the construction of impudent sophisms, the one party striving to prevent the lies of Asclepiades from ever being refuted, and the other saying stupidly what Erasistratus had the sense to keep silence about.