Augustine of Hippo

(Lib. oct. Quæs. 73) For some things are joined to others in such a way as both to change and be changed, just as food, losing its former appearance, is both itself turned into our body, and we too are changed, and our strength is refreshed by it.b Further, a most subtle liquid, after the food has been prepared and digested in our veins, and other arteries, by some hidden channels, called from a Greek word, pores, passes through us, and goes into the draught.