"...In this book I speak of the human aura and its colors as being perceived by astral or clairvoyant vision for this is the way in which it is perceived and studied by the occultist. The occult teaching is that in the evolution of the race this astral vision will eventually become the common property of every human being it so exists even now and needs only development to perfect it. But modern physical science is today offering corroborative proof (though the same is not needed by the occultist who has the astral vision) to the general public of the existence of the human aura. In Europe especially a number of scientists have written on the subject of the aura and have described the result of the experiments in which the aura has been perceived and even photographed by means of fluorescent screens such as are used in taking X-Ray photographs etc. Leading authorities in England France and still more recently in Germany have reported the discovery (!) of a nebulous hazy radio-active energy or substance around the body of human beings. In short they now claim that every human being is radio-active and that the auric radiation may be registered and perceived by means of a screen composed of certain fluorescent material interposed between the eye of the observer and the person observed..."