Men of science in former ages worked in secret, and instead of publishing their discoveries, taught them in secret to carefully selected pupils. Their motives for adopting that policy are readily intelligible, even if the merits of the policy may seem still open to discussion. At all events, their teaching has not been forgotten; it has been transmitted by secret initiation to men of our own time, and while its methods and its practical achievements remain secrets in their hands, it is open to any patient and earnest student of the question to satisfy himself that these methods are of supreme efficacy, and these achievements far more admirable than any yet standing to the credit of modern science.