credit, that he feared: that he was not satisfied with pointing
out remedies, but himself applied them, that he sat by my bedside among
my anxious friends, and came to see me at the crises of my disorder;
that no service was too troublesome or too disgusting for him to
perform; that he did not hear my groans unmoved; that among the numbers
who called for him I was his favourite case; and that he gave the others
only so much time as his care of my health permitted him: I should feel
obliged to such a man not as to a physician, but as to a friend. Suppose
again that my teacher endured labour and weariness in instructing me;
that he taught me something more than is taught by all masters alike;
that he roused my better feelings by his encouragement, and that at
one time he would raise my spirits by praise, and at another warn me
to shake off slothfulness: that he laid his hand, as it were, upon my
latent and torpid powers of intellect and drew them out into the light
of day; that he did not stingily dole out to me what he knew, in order
that he might be wanted for a longer time, but was eager, if possible,
to pour all his learning into me; then I am ungrateful, if I do not love
him as much as I love my nearest relatives and my dearest friends.

XVII. We give something additional even to those who teach the meanest
trades, if their efforts appear to be extraordinary; we bestow a
gratuity upon pilots, upon workmen who deal with the commonest materials
and hire themselves out by the day. In the noblest arts, however, those
which either preserve or beautify our lives, a man would be ungrateful
who thinks he owes the artist no more than he bargained for. Besides
this, the teaching of such learning as we have spoken of blends mind
with mind; now when this takes place, both in the case of the physician
and of the teacher the price of his work is paid, but that of his mind
remains owing.

XVIII. Plato once crossed a river, and as the ferryman did not ask him
for anything, he supposed that he had let him pass free out of respect,
and said that the ferryman had laid Plato under an obligation. Shortly
afterwards, seeing the ferryman take one person after another across the
river with the same pains, and without charging anything, Plato declared
that the ferryman had not laid him under an obligation. If you wish me
to be grateful for what you give, you must not merely give it to me, but
show that you mean it specially for me; you cann