The chemistry of vegetable and animal physiology / by G.J. Mulder ; translated from the Dutch by P.F.H. Fromberg ; with an introduction by J.F.W. Johnston.

  • Mulder, G. J. (Gerrit Jan), 1802-1880.
Date:
1845
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Licence: Public Domain Mark

Credit: The chemistry of vegetable and animal physiology / by G.J. Mulder ; translated from the Dutch by P.F.H. Fromberg ; with an introduction by J.F.W. Johnston. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    572° F., and to gold and silver at a lower temperature. It had previously been discovered by Sir Humphry Davy, that platinum, if placed in the vapor either of alcohol or of ether, began to glow, and caused a combination between the vapor and the oxygen of the air. Spongy platinum was afterwards discovered by Edmund Davy, who observed that it possessed this property in so high a degree, that if the platinum was moistened with alcohol, acetic acid was produced from the alcohol while the platinum was glowing. Before the discov- ery of Thenard and Dulong, it had been remarked by Dbbe- reiner that hydrogen and oxygen could be combined together by means of spongy platinum. This discovery was extended by the two former to several other substances. The effect of deutoxide of hydrogen, (HO2), when in con- tact with various substances, has been classed by Berzelius with the same series of phenomena. It explodes, if brought in contact with platinum, silver, peroxide of manganese, and even with organic substances, such as fibrin. Oxygen is dis- engaged, and water (HO) remains.* In every case, where the solid substance can combine with the whole quantity of oxygen, there is of course only an ordinary chemical action; but if this combination does not take place, and if the action occurs on contact simply, the phenomenon is that which Berzelius calls catalysis. This term ought further to be used with reference to the change of alcohol into ether, by means of acids. Hydrate of sulphuric acid—the common oil of vitriol of the shops—into which alcohol is dropped at an elevated temperature, is not diluted by the water produced, but a mixture of oxide of ethyl and water distills oft'. Sulphuric acid, therefore, catalyzes at that temperature the elements of alcohol into oxide of ethyl and water, without itself combining with either. The same effect is produced by other acids, especially if they are power- ful. To the same class we refer the changes, produced on starch by sulphuric acid, transforming it either into dextrine or into sugar—the changes which are produced by acids on starch, gum, sugar, forming humic acid, ulmic acid, and for- * It is now known that at the same time part of the oxygen is com- bined with the fibrin. !ind oxy-protein produced. (Scheikundige On- derzoekingen, by Mulder, D. ].)