With the discovery that radium transforms itself into helium, and that, indeed, all the so-called radioactivities of the heavy metals are probably due to a natural transmutation process constantly at work, the ideas of the older chemists cease entirely to be a subject for amusement. The physical chemists of the present day are very ready to admit that the old teaching of the absolute independence of something over seventy elements is no longer tenable, except as a working hypothesis. The doctrine of "matter and form," taught for so many centuries by the scholastic philosophers, which proclaimed that all matter is composed of two principles, an underlying material substratum, and a dynamic or informing principle, has now more acknowledged verisimilitude, or lies at least closer to the generally accepted ideas of the most progressive scientists, than it has at any time for the last two or three centuries. Not only the great physicists, but also the great chemists, are speculating along lines that suggest the existence of but one form of matter, modified according to the energies that it possesses under a varying physical and chemical environment. This is, after all, only a restatement in modern times of the teaching of St. Thomas of Aquin, in the thirteenth century. It is not surprising, then, that there should be a reawakening of interest in the lives of some of the men, who, dominated by some of the earlier scholastic ideas, by the tradition of the possibility of finding the philosopher's stone, which would transmute the baser metals into the precious metals, devoted themselves with quite as much zeal as any modern chemist to the observation of chemical phenomena. One of the most interesting of these--indeed, he might well be said to be the greatest of the alchemists--is the man whose only name that we know is that which appears on a series of manuscripts written in the High German dialect of the end of the fifteenth and the beginning of the sixteenth century. That name is Basil Valentine, and the writer, according to the best historical traditions, was a Benedictine monk. The name Basil Valentine may only have been a pseudonym, for it has been impossible to trace it among the records of the monasteries of the time. That the writer was a monk, however, there seems to be no room for doubt, for his writings give abundant evidence of it, and, besides, in printed form they began to have their vogue at a time when there was little likelihood of their being attributed to a monastic source, unless an indubitable tradition connected them with some monastery.