art of medicine rightly understood.  In our order we hold most noble,—­first, that knowledge which elevates the intellect; secondly, that which preserves the body.  But the mere art (extracted from the juices and simples) which recruits the animal vigour and arrests the progress of decay, or that more noble secret, which I will only hint to thee at present, by which heat, or caloric, as ye call it, being, as Heraclitus wisely taught, the primordial principle of life, can be made its perpetual renovater,—­these I say, would not suffice for safety.  It is ours also to disarm and elude the wrath of men, to turn the swords of our foes against each other, to glide (if not incorporeal) invisible to eyes over which we can throw a mist and darkness.  And this some seers have professed to be the virtue of a stone of agate.  Abaris placed it in his arrow.  I will find you an herb in yon valley that will give a surer charm than the agate and the arrow.  In one word, know this, that the humblest and meanest products of Nature are those from which the sublimest properties are to be drawn.”

“But,” said Glyndon, “if possessed of these great secrets, why so churlish in withholding their diffusion?  Does not the false or charlatanic science differ in this from the true and indisputable,—­that the last communicates to the world the process by which it attains its discoveries; the first boasts of marvellous results, and refuses to explain the causes?”

“Well said, O Logician of the Schools; but think again.  Suppose we were to impart all our knowledge to all mankind indiscriminately,—­alike to the vicious and the virtuous,—­should we be benefactors or scourges?  Imagine the tyrant, the sensualist, the evil and corrupted being possessed of these tremendous powers; would he not be a demon let loose on earth?  Grant that the same privilege be accorded also to the good; and in what state would be society?  Engaged in a Titan war,—­the good forever on the defensive, the bad forever in assault.  In the present condition of the earth, evil is a more active principle than good, and the evil would prevail.  It is for these reasons that we are not only solemnly bound to administer our lore only to those who will not misuse and pervert it, but that we place our ordeal in tests that purify the passions and elevate the desires.  And Nature in this controls and assists us:  for it places awful guardians and insurmountable barriers between the ambition of vice and the heaven of the loftier science.”

Such made a small part of the numerous conversations Mejnour held with his pupil,—­conversations that, while they appeared to address themselves to the reason, inflamed yet more the fancy.  It was the very disclaiming of all powers which Nature, properly investigated, did not suffice to create, that gave an air of probability to those which Mejnour asserted Nature might bestow.

Thus days and weeks rolled on; and the mind of Glyndon, gradually fitted to this sequestered and musing life, forgot at last the vanities and chimeras of the world without.