GROUND-AIR IN ITS HYGIENIC RELATIONS. 291 



of a river grains of a white metal, whicli 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 ham- 

 mered, 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 importa- 

 tion was prohibited by the Spanish Government, because there was 

 danger of its high specific gravity leading to its use for the adul- 

 teration 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 inter- 

 course 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 raitch 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 utiUty 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 fre- 

 quently, 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 com- 

 plete, what requires no further investigation, but also to point out 

 to you much greater fields of hygiene, Avhere 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- 



