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Page:Popular Science Monthly Volume 35.djvu/833

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THE CHEMIST AS A CONSTRUCTOR.

like purpose had proved futile. It was Loew who in 1886 succeeded in preparing a more concentrated solution of formaldehyde than could be made before. He found that the vapor of wood-spirit in contact with heated oxide of copper furnishes formaldehyde in abundant quantities. Moreover, he found that condensation of this aldehyde to sugar is easily achieved by digesting a solution of it with slaked lime. The product, to which he gave the name of formose, has exactly the composition of grape-sugar; it has a sweet taste, and acts on Fehling's solution as sugar does; the resemblance extends to several further properties; but still there are some slight points of difference, which have caused a few chemists to raise objections as to its classification among sugars. The question of the formation of sugar from aldehydes would perhaps have remained undecided for the present, had not recent experiments, made by Fischer and Tafel, confirmed the statements before mentioned by giving evidence of the formation of sugar by condensation from other aldehydes. Their statements were supported by Grimaux, who, by subjecting glycerin to the oxidizing influence of finely divided platinum, obtained a substance resembling grape-sugar in all its properties, which in contact with yeast even undergoes fermentation, producing alcohol and carbonic acid, and hereby manifesting the character of a true sugar.

These results not only enable us to prepare by a chemical process this substance, formerly only known to be produced by living plants, but they also afford important facts and proofs which justify us in expecting the synthetical formation of other compounds playing a part in the vegetation of plants, thereby acquiring an insight into those complicated phenomena of organic life which science hitherto has in vain tried to explain. By perfecting our comprehension of natural processes we become more and more enabled to utilize them for the advancement and the welfare of mankind—an attainment which constitutes the chief aim and purpose of natural science in general.

 


 
The experiments of E. H. S. Bailey and E. L. Nichols, upon the delicacy of the sense of taste, indicate that the impression derived from bitter substances far exceeds that arising from any other class. The order as to the substances experimented upon is bitters, acids, saline substances, and sweets. The potency of quinine is very remarkable. Men who tasted could detect on the average one part of it in 390,000, and women one part in 456,000 parts of water; and to sugar it stood in potency as very nearly 2,000:1. The range of individual sensitiveness is very extensive. "With all the substances tried, except salt, the taste of the women was more delicate than that of the men. But while some of the persons experimented with could detect with certainty one part of quinine in 5,120,000 of water, others failed to notice one part in 160,000. The sense of taste does not appear to be blunted for any substance by long-continued habitual use of it.