De parasito sive artem esse parasiticam

That Parasitic is based not only on knowledge, but on exercised knowledge, you may readily assure yourself from this fact: the knowledges that belong to the other arts often remain unexercised for days and nights and months and years, and yet the arts are not lost to those who possess them ; but if the . parasite’s knowledge is not in exercise daily, not only the art, I take it, but the artist himself, is lost thereby !