Plutarch, De Iside et Osiride
Frank Cole Babbitt, Ed.

It is true that most people are unaware of this very ordinary and minor matter : the reason why the priests remove their hair and wear linen garments.¹ Some persons do not care at all to have any knowledge about such things, while others say that the priests, because they revere the sheep,² abstain from using its wool, as well as its flesh ; and that they shave their heads as a sign of mourning, and that they wear their linen garments because of the colour which the flax displays when in bloom, and which is like to the heavenly azure which enfolds the universe. But for all this there is only one true reason, which is to be found in the words of Plato³; ‘for the Impure to touch the Pure is contrary to divine ordinance.’ No surplus left over from food and no excrementitious matter is pure and clean ; and it is from forms of surplus that wool, fur, hair, and nails originate and grow.⁴ So it would be ridiculous that these persons in their holy living should remove their own hair by shaving and making their bodies smooth all over,⁵ and then should put on and wear the hair of domestic animals. We should believe that when Hesiod⁶ said, [p. 15]

Cut not the sere from the green when you honour the gods with full feasting,
Paring with glittering steel the member that hath the five branches,

he was teaching that men should be clean of such things when they keep high festival, and they should not amid the actual ceremonies engage in clearing away and removing any sort of surplus matter. But the flax springs from the earth which is immortal; it yields edible seeds, and supplies a plain and cleanly clothing, which does not oppress by the weight required for warmth. It is suitable for every season and, as they say, is least apt to breed lice ; but this topic is treated elsewhere.⁷