Notes on physiology / by Henry Ashby.

  • Henry Ashby
Date:
1889
Catalogue details

Licence: Public Domain Mark

Credit: Notes on physiology / by Henry Ashby. Source: Wellcome Collection.

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    Urea, Calcium, in bones and teeth and fluids. Magnesium accompanies lime. II. The Organic Crystalline Bodies are very numerous ; for the most part they are the result of the disintegration of albuminous material, and nearly all contain nitrogen. The principal members of this group, are urea, uric acid, xanthin, hypoxanthin, hippuric acid, kreatin, kreatinin, lactic acid, lecithin, neurin, cerebrin, leucin, tyrosin, and cholesterin. Urea, CH4N2O or CO(NH2)2 forms the chief constituent of the solid portions of the urine of man and the carnivorous animals ; it is also found, but less freely, in the urine of herbivorous animals, rep- tiles, and birds. It exists in minute quantities in the blood, lymph, and liver. It is found in larger quan- tities in all the fluids of the body in advanced Bright's disease. Preparation^artificially.—By heating a mixture of potassic ferrocyanide and manganic dioxide on an iron sheet, potassic cyanate is formed, and is dissolved out with water. The potassic cyanate is treated with ammonium sulphate, ammonium cyanate and potassic sulphate being formed ; the potassic salt is removed by crystallisation, and the mother liquor, on evapora- tion to dryness, and extraction of the dried residue with alcohol, yields urea. It can also be made artificially by heating am- monium cyanate, a rearrangement of atoms taking place. NH4CNO = (NH2)2CO Ammonium cyanate — Urea. From urine,—The urine is evaporated to a thin syrup, and its own volume of colourless nitric acid added ; nitrate of urea is formed and readily crystal- lises. The nitrate is decolourised by animal charcoal and recrystallised. To obtain the urea pure, the nitrate is decomposed by barium carbonate, the B 2
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