Scribonius Largus, Medical Compounds, Preface

raro enim aliquis priusquam se suosque tradat medico, diligenter de eo iudicat, cum interim nemo ne imaginem quidem suam committat pingendam nisi probato prius artifici per quaedam experimenta atque ita electo.

It is rare that, before someone hands himself or his household over to a doctor, he makes a careful judgement about him; but meanwhile no one would entrust even the painting of his portrait to anyone except an artist whom he had previously tested by means of some trial-runs and chosen in that way.