SECT. XXXIII. Of Veins and Arteries.

Let us consider the flesh. It is covered in certain places with a soft and tender skin, for the ornament of the body. If that skin, that renders the object so agreeable, and gives it so sweet a colour, were taken off, the same object would become ghastly, and create horror. In other places that same skin is harder and thicker, in order to resist the fatigue of those parts. As, for instance, how harder is the skin of the feet than that of the face? And that of the hinder part of the head than that of the forehead? That skin is all over full of holes like a sieve: but those holes, which are called pores, are imperceptible. Although sweat and other transpirations exhale through those pores, the blood never runs out that way. That skin has all the tenderness necessary to make it transparent, and give the face a lively, sweet, and graceful colour. If the skin were less close, and less smooth, the face would look bloody, and excoriated. Now, who is that knew how to temper and mix those colours with such nicety as to make a carnation which painters admire, but never can perfectly imitate?

There are in man's body numberless branches of blood-vessels. Some of them carry the blood from the centre to the extreme parts, and are called arteries. Through those various vessels runs the blood, a liquor soft and oily, and by this oiliness proper to retain the most subtle spirits, just as the most subtle and spirituous essences are preserved in gummy bodies. This blood moistens the flesh, as springs and rivers water the earth; and after it has filtrated in the flesh, it returns to its source, more slowly, and less full of spirits: but it renews, and is again subtilised in that source, in order to circulate without ceasing.