Sect. XXXIII. of Veins and Arteries
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.