Volume 1

Animal chemistry : with reference to the physiology and pathology of man / by Franz Simon ; translated and edited by George E. Day.

  • Johann Franz Simon
Date:
1845-1846
Catalogue details

Licence: Public Domain Mark

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

Provider: This material has been provided by The University of Glasgow Library. The original may be consulted at The University of Glasgow Library.

    118/430 (page 94)
    lu this case heat will develop a pellicle on the surface, and acetic acid will throw down a precipitate, which is soluble in an excess of the test: the acid must therefore be added with caution. It must not however be forgotten that if much albuminate of soda, and at the same time no free albumen be present in the fluid, no coagidation will occur on the application of heat, but a pellicle will be formed on the sm'face. This is however a case of very rare occurrence, and the difficulty may be readily solved by the addition of acetic acid which will precipi- tate casein but not albumen. If a fluid which contains casein presents a whitish turbid appearance (as for instance, milk, the milky fluid which is found in the breasts during the later stages of pregnancy, the mane in certain pathological states, &c.) the presence of butter, and in most instances, of sugar, may be inferred. If the ferrocyanide of potassium does not produce any tur- bidity in the fluid which has been previously acidulated with dilute hydrochloric acid, no protein-compound is present. 2. If the addition of acetic acid to the fluid renders it turbid, or throws down a precipitate, which does not redissolve in an excess of the test, then pyin or mucini is present. In this case, a copious precipitate, insoluble in an excess of the test, is thrown down by alum. In order to show that the precipitate contains no casein, we may dissolve it in dilute hydrochloric acid, and add ferrocyanide of potassium: no pre- cipitate will be thrown down.2 3. If allantoin, uric acid, or hippuric acid are suspected to be present, a considerable quantity of the fluid must be boiled in order to coagulate any albumen that may be present, and must then be filtered and evaporated to one fom’th of its original volume. Fluids of this natoe are generally of a yellowish colour, may be either clear or turbid, and may or may not contain albumen. In the examination of the allantoic fluid, crystals of aUan- toin are gradually formed, wliich, after being purified by ‘ [Mucin is the peculiar animal matter of mucus; a brief notion of its leading cha- racters is given in the chapter on the “ Secretions of Mucous Membranes.”] As chondrin and glutin are not constituents of any of the animal fluids, we have deemed it unnecessary to notice them in the text.