Attraction Verus Void

I will refute those who object to the principle of attraction.

Nobody has explained any other cause or means for the secretion of urine.

We would appear mad if we said that:

• the urine passes into the kidneys as a vapour.
• a vacuum is refilled
• This idea is foolish in the case of blood
• It is impossible and nonsensical in the case of the urine.

This is one blunder made by those who dissociate themselves from the principle of attraction.

Another is that which they make about the secretion of yellow bile.

For in this case, too, it is not a fact that when the blood runs past the mouths [stomata] of the bile-ducts there will be a thorough separation out [secretion] of biliary waste-matter.

Some suppose that it is not secreted but carried with the blood all over the body.

But Erasistratus himself supposed that:

• Nature took thought for the animals’ future, and was workmanlike in her method
• the biliary fluid was useless in every way for the animals

These 2 things are incompatible.

For how could Nature be still looked on as exercising forethought for the animal when she allowed a noxious humour such as this to be carried off and distributed with the blood?

Their greatest and most obvious error is:

For if the yellow bile adjusts itself to the narrower vessels and stomata, and the blood to the wider ones, for no other reason than that blood is thicker and bile thinner, and that the stomata of the veins are wider and those of the bile-ducts narrower, then it is clear that this watery and serous superfluity, too, will run out into the bile-ducts quicker than does the bile, exactly in proportion as it is thinner than the bile!

How can it not run out?

They answer that urine is thicker than bile!

This is against evidence.

If bile is thinner than blood because it runs more, then, since the serous residue passes through fine linen or lint or a sieve more easily even than does bile, by these tokens bile must also be thicker than the watery fluid.

Bile is NOT thinner than the serous superfluities.