Indian Sages to whom Evolution was a familiar notion ages before Paul of Tarsus was born." (P. 150, "Science and Hebrew Tradition.")] In the second aphorism of the fourth chapter (see "Raja Yoga," by Swami Vivekananda, p. 210) it is said, "The Evolution into another species is caused by the in-filling of nature." The nature is filled not from without but from within. Nothing is superadded to the individual soul from outside. The germs are already there, but their development depends upon their coming in contact with the necessary conditions requisite for proper manifestation. We sometimes see a wicked man suddenly become saintlike. There are instances of murderers and robbers becoming saints. A religionist will explain the cause of their sudden change, by saying that the grace of the Almighty has fallen upon them and transformed their whole nature. But Vedanta says that the moral and spiritual powers that remained latent in them have been roused up, and the result is the sudden transformation. None can tell when or how the slumbering powers will wake up and begin to manifest. The germ of life, or the individual soul as it is ordinarily called, possesses infinite possibilities. Each germ of life is studying, as it were, the book of its own nature by unfolding one page after another. When it has gone through all the pages, or, in other words, all the stages of evolution, perfect knowledge is acquired, and its course is finished. We have read our lower nature by turning each page, or, in other words, by passing through each stage of animal life from the minutest bioplasm up to the present stage of existence. Now we are studying the pages which deal with moral and spiritual laws. If any one wants to read any page over again he will do it. Just as in reading a book, if anybody feels particularly interested in any page or chapter he will read it over and over again and will not open a new page or a new chapter until he is perfectly satisfied with it. Similarly, in reading the book of life, if the individual soul likes any particular stage, he will stay there until he is perfectly satisfied with it; after that he will go forward and study other pages. One may read very slowly, and another very fast; but whether we read slowly or rapidly each one of us is bound to read the whole book of nature and attain to perfection sooner or later.