Now the fact is that there are many methods by which it may be developed, but only one which can be at all safely recommended for general use--that of which we shall speak last of all. Among the less advanced nations of the world the clairvoyant state has been produced in various objectionable ways; among some of the non-Aryan tribes of India, by the use of intoxicating drugs or the inhaling of stupefying fumes; among the dervishes, by whirling in a mad dance of religious fervour until vertigo and insensibility supervene; among the followers of the abominable practices of the Voodoo cult, by frightful sacrifices and loathsome rites of black magic. Methods such as these are happily not in vogue in our own race, yet even among us large numbers of dabblers in this ancient art adopt some plan of self-hypnotization, such as the gazing at a bright spot or the repetition of some formula until a condition of semi-stupefaction is produced; while yet another school among them would endeavour to arrive at similar results by the use of some of the Indian systems of regulation of the breath. All these methods are unequivocally to be condemned as quite unsafe for the practice of the ordinary man who has no idea of what he is doing--who is simply making vague experiments in an unknown world. Even the method of obtaining clairvoyance by allowing oneself to be mesmerized by another person is one from which I should myself shrink with the most decided distaste; and assuredly it should never be attempted except under conditions of absolute trust and affection between the magnetizer and the magnetized, and a perfection of purity in heart and soul, in mind and intention, such as is rarely to be seen among any but the greatest of saints. Experiments in connection with the mesmeric trance are of the deepest interest, as offering (among other things) a possibility of proof of the fact of clairvoyance to the sceptic, yet except under such conditions as I have just mentioned--conditions, I quite admit, almost impossible to realize--I should never counsel anyone to submit himself as a subject for them.