Note 78 — BOOK I. (continued 5)

Let no one, from this instance, altogether condemn the use of varnishes in the restoration of paintings; for by the application of mastic, and of gum water, according to all the most recent experiments, the colour does not suffer. But oil is injurious to ancient paintings, for the new never becomes incorporated with the old, and, in a short time, every fresh touch is converted into a stain.