Copy 1, Volume 1

Animal chemistry with reference to the physiology and pathology of man / By Dr. J. Franz Simon. Translated and edited by George E. Day.

  • Simon, Johann Franz, 1807-1843.
Date:
1845-1846
Catalogue details

Licence: Public Domain Mark

Credit: Animal chemistry with reference to the physiology and pathology of man / By Dr. J. Franz Simon. Translated and edited by George E. Day. Source: Wellcome Collection.

    115/426 (page 95)
    recrystallization, and dissolved in water, cannot be precipitated by acetate of lead, nitrate of silver, or nitrate of the black oxide of mercury. If the fluid, durmg evaporation, gives off an urinous odour some hydrochloric acid must be added, and it must be allowed to stand for some time. If acicular crystals are formed, which, after being purified by recrystallization, and dissolved in water containing enough alkali to neutralize the acid of the crystals, give a white precipitate with the above-named tests, an orange with the perchloride of iron, and when moistened with nitric acid, and warmed, do not assume a purple-red colour, they consist of hippuric acid. If however the crystals are very minute, are not readily dissolved in water, and give, when moistened with nitric acid and warmed, a purple-red stain, they are wric acid crystals. 4. If the fluid which we are examining is of a brownish yellow colour, and if on treating a little of it with an excess of nitric acid, the colour successively changes to green, blue and red, then bilipheein is present. 5. On evaporating a portion of the fiuid to dryness, pulver- ising it, and boiling it with ether, we obtain, by the evaporation of the ethereal solution, a fatty residue. If it be fluid, it is composed of olein, if it have a tendency to be solid, either stearin or margarin, or both are also present. The fatty acids, and probably free lactic acid, with traces of other sub- stances may be present, especially if the ether contained any alcohol or water. These substances remain in solution, on washing the fatty residue with water. The lactic acid may be easily recognized by its acid reaction ; and the fatty acids may be detected by the addition of acetate of lead or acetate of copper to their alcoholic solutions. They are completely pre- cipitated in this manner, and a residue of pure fat is left, which must be again washed and the water removed by evaporation. The fat must then be saponified ; if a portion of it resists this process, cholesterin or serolin, or both, must constitute a por- tion of the fatty residue. They must be taken up by ether, after the saponified portion has been evaporated to dryness. Serolin is less soluble in alcohol, and melts at a lower tem- perature than cholesterin,' by which means the two fats may 1 Serolin melts at 95°, cholesterin at about 275°.]