of a river grains of a white metal, which was not affected by fire, and appeared, therefore, to be a noble metal. Quantities were brought to Europe, and the new metal received the modest name of platina (low silver), this being a diminutive of la plata (silver). The masters of the Mint, the gold and silver smiths, had soon formed their ideas about the new metal; it could neither be melted by itself, nor hammered, nor rolled, nor dissolved in aqua-fortis. It was only soluble in aqua-regia and other melted metals, but the combinations were all brittle and discolored; in short, it came to be considered a perfectly useless metal, practically worth less than lead and iron. Its importation was prohibited by the Spanish Government, because there was danger of its high specific gravity leading to its use for the adulteration of gold. What platina there was in the country already was thrown into the sea by order. But Science, who makes no difference between the useful and useless, and considers everything useful which increases our insight into the things that are, has quietly held intercourse with the outcast metal; she learned how to tame the shrew, and since Wollaston platina is considered to be one of the most pliable and useful of metals; just what were originally considered its vices have enhanced its value so much in the course of time that weight for weight the "low silver" is paid seven times as much for as the "high silver."
Modern times have not ceased furnishing numerous examples of the same kind, showing that it is not the business of science to ask for the immediate profit, for the immediate practical use. They do not fail to come forth in time.
Science may point to the words of the Bible: "But seek ye first the kingdom of God and his righteousness, and all these things shall be added unto you." All sciences are provinces of God's infinite kingdom, and in them, as everywhere in God's kingdom. Justice is dealt by Truth alone. This was my standpoint, which helped me over the doubts I might have had concerning the utility of these lectures. It seemed to me that the principal thing was not to present to you a series of practical applications and contrivances, but a series of truths, which carry in themselves their use and applicability, and impose their authority in proportion as they are talked over more frequently, understood more clearly, and felt more vividly.
But I wanted to tell you the whole truth about the things which formed the subject of my lectures, and it became my duty to draw your attention not only to what is positively known, what is complete, what requires no further investigation, but also to point out to you much greater fields of hygiene, where scarcely a seed has been sown. Otherwise I should probably have jeopardized the only and immediate practical use which my lectures can have here, and which I believe to be this: that the conviction may spread and take root everywhere, that hygiene has been neglected until now, prac-
