The Urinary System
Table of Contents
Erasistratus entirely passed over the view held by Hippocrates.
The stomach does not exercise any attraction.
But when he is dealing with anadosis he does not mention the Hippocratic view.
Hippocrates lies in saying ‘The flesh attracts both from the stomach and from without,’ for it cannot attract either from the stomach or from without.”
Or if he had thought it worth while to state that Hippocrates was wrong in criticizing the weakness of the neck of the uterus, “seeing that the orifice of the uterus has no power of attracting semen”
I say to him:
Give us proof. State a definite objection so 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?
The stomach does not appear to exercise any traction.
But there is no peristalsis of the gullet.
Peristalsis is when the upper parts of the gullet contract the lower parts dilate?
How 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?
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.
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.
Erasistratus knew of this faculty. But he neither mentioned it nor denied it. He did not say how the secretion of urine happens.
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,150 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 expression 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 cava154 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;155 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?
Erasistratus realized that all these ideas were open to many objections.
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 fail to make oneself utterly ridiculous.
This is why:
- Erasistratus kept silence
- Asclepiades lied
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,157 to collect in the bladder.