The thirst of desire is never filled, nor fully satisfied.
It is our duty, my young friends, to resist old age.
The roots of knowledge are bitter, but its fruit are sweet.
No one has leave to sin.
A careful physician . . . before he attempts to administer a remedy to his patient, must investigate not only the malady of the man he wishes to cure, but also his habits when in health, and his physical constitution.
Nothing is more disgraceful than insincerity.