A treatise on the blood, inflammation, and gun-shot wounds / by John Hunter ; with notes by James F. Palmer.

  • John Hunter
Date:
1840
Catalogue details

Licence: Public Domain Mark

Credit: A treatise on the blood, inflammation, and gun-shot wounds / by John Hunter ; with notes by James F. Palmer. 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.)

    59/618
    not, however, hinder its coagulation by heat; such as vinegar, acid of lemon, salt of wormwood, nitre, sea-salt.* Serum coagulates with spirits of wine, in about equal quantities, into a sort of curd and whey, which upon heating becomes some- thing like a jelly, but the spirit seems to evaporate. It coagulates with volatile spirits into a milky fluid, which becomes like a jelly upon heating; it requires a greater proportion of the spirit than the serum, and the spirit seems chiefly to evaporate. When mixed with salt of hartshorn it does not coagulate with heat, but makes a large effervescence till the whole is formed into froth. This again becomes a fluid by the froth subsiding, but at last it forms a sort of coagulum which is not tough. Being mixed with water, and let to stand for twelve hours, it coagulates like pure serum upon heating. If this be mixed with sal. cornu cervi, as above, it rather becomes * [According to the best analyses, synovia and the white of egg do not contain any fibrin, consequently these substances have no resemblance to the coagulable lymph of the blood. Undiluted albumen coagulates at a temperature of 160°, and is rendered opake at 212°, even when diluted with 1000 parts of water, unless excess of free or carbonated alkali be present, in which case it will not be coagulated by heat. (See Burrows in Med. Gazelle, xiv. 555.) It is a singular fact that serum when diluted with 20 parts of water is not precipitable by a temperature of 165°. Galvanism and the mineral acids are very excellent tests of the presence of albumen, and so are the solutions of the ferrocyanate of potash and corrosive sublimate. Albumen diluted with 2000 parts of water may easily be detected by the two latter. The mode in which heat, galvanism, alcohol, acids, and a variety of other agents produce coagulation of the albumen has long been the subject of debate. The most general, and, as it appears to me, the most rational, explanation of the matter is as follows, viz., that the albumen of serous fluids is held in solution by means of a free alkali; but by heat the free soda of the serum is transferred to the water or united to the carbonic acid of the atmosphere; by acids it is neutralised, and by galvanism it is attracted to the negative pole of the trough. However, this explanation is not quite satisfactory. Dr. Bostock has shown not only that excess of acetic acid does not coagulate albumen, but that the quantity of free alkali present is too inconsiderable to produce the effect ascribed to it. Others have supposed that alcohol and acids coagulate albumen by abstracting the water; but it is possible to desiccate albumen by slow evaporation without necessarily destroying its distinctive property, which is that of being again soluble upon the addition of water. The mineral salts do not merely precipitate albumen from its solution, but chemically combine with it, so as to produce specific compounds. Dr. Turner has suggested that albumen combines directly with water at the moment of being secreted, at a time that its particles are in a state of minute division ; but as its affinity for that liquid is very feeble, the com- pound is decomposed by slight causes, and the albumen thereby rendered quite insoluble. Silica affords an instance of a similar phenomenon. (Elem. ofChem. 4th edit., p. 868.) But the cases are not analogous. Albumen admits of being dried at a temperature below 150°, and even of being heated to 212°, without losing its solubility; whereas silica remains perfectly insoluble after it has once been precipitated. The truth seems to be that albumen is one of those compounds which allow of a new arrangement of their molecular particles with exceeding facility, similar to muscular fibre, which is rendered permanently rigid by a temperature at least 20° below that which is required to coagulate albumen. It is scarcely there- fore correct to say that albumen before and after coagulation are identical sub- stances.]