but if they think upon the corresponding centre in the body, a good deal—much harm—may come of it. “Meditate on the navel,” it is also said. This means the solar plexus, for there is a close connection between the two. But to meditate on that is to incur the danger of a serious nervous disorder, almost impossible to cure. All who know how many people in India suffer through these practices, ill-understood, recognize that it is not wise to plunge into them without some one to tell you what they mean, and what may be safely practiced and what not. The other part of the Yoga literature is a small book called the sutras of Patanjali. That is available, but I am afraid that few are able to make much of it by themselves. In the first place, to elucidate the Sutras, which are simply headings, there is a great deal of commentary in Sanskrit, only partially translated. And even the commentaries have this peculiarity, that all the most difficult words are merely repeated, not explained, so that the student is not much enlightened. Some Definitions There are a few words, constantly recurring, which need brief definitions, in order to avoid confusion; they are: Unfolding, Evolution, Spirituality, Psychism, Yoga and Mysticism. “Unfolding” always refers to consciousness, “evolution” to forms. Evolution is the homogeneous becoming the heterogeneous, the simple becoming complex. But there is no growth and no perfectioning for Spirit, for consciousness; it is all there and always, and all that can happen to it is to turn itself outwards instead of remaining turned inwards. The God in you cannot evolve, but He may show forth His powers through matter that He has appropriated for the purpose, and the matter evolves to serve Him. He Himself only manifests what He is. And on that, many a saying of the great mystics may come to your mind: “Become,” says St. Ambrose, “what you are”—a paradoxical phrase; but one that sums up a great truth: become in outer manifestation that which you are in inner reality. That is the object of the whole process of Yoga. “Spirituality” is the realisation of the One. “Psychism” is the manifestation of intelligence through any material vehicle.[4] [4] See _London Lectures_ of 1907, “Spirituality and Psychism”. “Yoga” is the seeking of union by the intellect, a science; “Mysticism” is the seeking of the same union by emotion.[5] [5] The word yoga may, of course, be rightly used of all union with the self, whatever the road taken. I am using it here in the narrower sense, as peculiarly connected with the intelligence, as a Science, herein following Patanjali.