3d solution. Sd solution. 4th solution, forming an upper stratum to the pus. It was decanted for examination. (a) On exposure to fire it became turbid like milk, as soon as the temperature was elevated to 165°, but did not become thicker at a greater-elevation, (b) On evaporation to dryness, the residue amounted to about one fifteenth of the weight of the liquid from the serous pus, and to one twentieth from the three other kinds; in place of about one tenth, as from the first decanted liquid, (Sect. I, 4); and as from serum of blood. The residuary matters were of the same kind as those above described, Sect. II, 2-6. (c) Three ounces by measure of distilled water having been again mixed with each of the four kinds of pus, and, in 48 hours, two ounces measure of decanted limpid fluid from each having been evaporated to dryness, residues of the same kind, in the same proportions, and in nearly the same quantities as before, were obtained (b). These decanted fluids became nearly as turbid as the former, on raising their temperature to 165°. (d) Distilled water was added a third time, in the quantity of eight ounces by measure, to each of the four parcels of pus under examination; and, after 48 hours repose, six ounces of limpid fluid were poured off from each of them. At the temperature of 165°, the decanted fluids became turbid; that of the serous pus more so than the others. On evaporation to dryness, a much smaller quantity of residue was obtained than before, viz. one sixtieth from the serous pus, and one seventieth from the others; and it consisted of the same kind of substances as above described; but the muriate of soda and potash were in smaller proportion than before. It (e) A fourth time distilled water, in the quantity of a pint, was mixed with the present four parcels of pus; and, after standing 48 hours, three fourths of a pint of clear colourless liquid was poured off from each of them. became slightly turbid and whitish on boiling. On evaporation, each parcel afforded about of the fluid employed. The residues now consisted of animal matter, with a much smaller proportion than before of muriate of soda, phosphate phosphate of lime, and potash- nothing else could now be traced. (f) Distilled water, in the quantity of a pint, was once 5th solution. more mixed with the four sorts of purulent matter under- going inquiry. After 48 hours, a pint of liquid was de canted from off each of them; but being slightly turbid, they were left to stand 24 hours. By this time a sediment was deposited from each of the liquors; but being still, though very slightly, turbid, they were filtrated through suitable paper. They were then transparent. The transparent filtrated liquors had their transparency disturbed by a boiling temperature. They became also slightly milky with nitrate of silver, but scarcely so with infusion of gall nut. On evaporation to the quantity of an ounce from each pint, the residuary liquids appeared slightly globular. These, on evaporation to dryness, yielded not more than one part of animal matter, from each 500 of the transparent filtrated liquids. (g) On standing three or four days in a cold room, the Residuum. parcels of pus, after the ablutions just related (a-f), exhibited a whey coloured liquor at the top, of which about of a pint was poured off from them. More turbid liquor was also separated from the washed pus, by pouring it upon a porous cotton cloth strainer, which left purulent matter of the consistence of starch mucilage, amounting to about one half the original weight. (h) The pus freed from coagulable limpid liquid by re- Its properties. peated ablutions (a-h) was white as snow-equal in consistence-perfectly smooth-the 4th kind was less viscid than before, but the others were more so-no smell-not at all disposed to putrefy-on elevating its temperature to 165° and higher, it did not coagulate into one mass, nor into clots, or large masses of curd, but a watery fluid separated from a fine soft somewhat curdlike opaque fluid; which did not become more curdy, even on boiling-it did not appear that above a grain of this part, or state of pus, dissolved in 1000 waters-was highly globular under the microscope, and remained so, although coagulated by nitrate of silver; by infusion of gall nut; by alcohol; and supersulphate of alumina-with muriate of ammonia, nitrate of potash, and other neutral Different kinds of pus neutral salts, and with carbonate of potash, it produced a viscid semitransparent mass like expectorated half transparent matter-exposed to fire in a platina crucible, it was inflamed, but did not emit an offensive smell, and after continuing the ignition, the residue was a particle of half. fused matter, not amounting to, of the pus after ablution, nor above of the same matter exsiccated; it consisted of phosphate of lime and vitrified matter-no ammonia was perceivable, on mixing lime with this washed pus; nor mu¬ riatic acid on adding sulphuric acid. 2, (a) A tea spoonful of the creamlike pus, being agitated agitated in wa- in half a pint of distilled water, produced a milky fluid, with a number of small curdy particies suspended, but very few leafy or fibrous pieces or clots. ter. Bolled. (b) The serous pus being treated as just mentioned («), the same appearances ensued. (c) The curdy pus being agitated in the same manner in water, a number of clots, leafy, and fibrous masses, were seen suspended among fine small curdy particles in a pearly liquid. (d) The viscid pus being treated as just said, it required long continued and violent agitation, to diffuse it through the water, and then the appearances were as last described. 3. Pus of any kind, after boiling in twenty times its quantity of water, was quite as globular under the microscope as previously. With a smaller proportion of water, the mixture became very turbid, sometimes clots were formed in a pearl liquid, in which a fine sediment took place, which appeared much more globular than the clots or curdy masses. 4. In general, water in which pus has been agitated remains somewhat milky, with an abundant close white sediment; but after two, or three, or more ablutions, the water becomes clear on standing, and the sediment more curdy. SECT. IV. Agency of Alcohol of Wine. Action of al. The different kinds of exsiccated pus exposed to the cohol on pus. agency of this menstruum, and treated as described in a former former paper, Phil. Trans. 1809, P. II, p. 329*, the results were similar, except in the proportion of products. 1. These exsiccated substances afforded to this men struum a smaller proportion of potash, but as much animal oxide and muriate of soda, as mucous sputum. 2. The undissolved matter left after repeated digestions in this menstruum afforded the same substances, but in smaller proportions, as mucous sputum. 3. Equal bulks of fresh pus, and rectified spirit of wine, afford a much thicker and more milky liquor, with a closer sediment, than expectorated mucous matter. SECT. V. Agency of acetous Acid. tous acid on pus. The purulent matters mixed with this acid became curdy, Action of ace and rendered it milky; but on standing, a close white sediment appeared, the liquid above being clear, except in the case of the viscid pus, which exhibited leafy and fibrous inasses, as hath been described with mucous sputum. By repeated digestion of the different kinds of pus in this menstruum, I obtained the same results, except the proportions of acetite of potash, and muriate of soda being smaller, as related in a former paper on mucous expectorated matter. Phil. Trans. 1809, P. II, p. 336 †. SECT. VI. Some Experiments with different Objects, especially to distinguish Pus and Mucus. on pus and 1. In the agency of sulphuric, nitric, and muriatic acids, Comparative in sufficient quantity to dissolve and decompound the sub- experiments stances under inquiry, I could perceive no important diffe- mucus, with rence between them. The purulent matters indeed remineral acids, quired a much greater proportion completely to dissolve them, than the transparent sputum. Also the more opaque and dense the sputum, the greater the resistance to dissolution. Sulphuric acid produced black liquids like those containing charcoal, smelling strongly of muriatic acid; but on dilution with water, they became clear. No precipita ⚫ Journal, Vol. XXV, p. 260. mineral acids vegetable acids, fixed alkalis and lime, tion occurred on dilution with water, and on saturation with the fixed alkalis, but a trifling sediment appeared, which redissolved on the addition of the above acids. 2. The mineral acids diluted, or added in small proportion, and the vegetable acids, coagulate variously pus and mucous fluids. Some become merely milky fluids, others curdy fluids, others afford fibrous and leafy masses in a transparent liquor, and others give a uniform thick mass of curd. On standing the deposits are accordingly of various forms, and the liquors above of various appearances; but I could discover no constant characteristic property of the substances by these experiments, as some writers have asserted. 3. The solid fixed alkalis, or lime, mixed with expectorated mucus, occasion a stronger smell of ammonia than with pus; or than with muco-purulent sputum. Some use may be perhaps made of this easy experiment to judge of the nature of varieties of the fluids in question, particularly as far as depends on the proportion of ammonia; for sometimes it cannot be perceived by the smell on mixing alkalis, but can by muriatic acid giving white vapours. Concenstrong solutons of alkalis, trated liquid alkalis, added to both pus and mucus, dissolve them to produce clear liquids, except small curdy parts and motes. These curdy parts and motes resist dissolution also for some time even in nitric acid, and seem to be self-coagulated lymph. They are in much greater proportion in pus than mucus. The addition of acids to these alkaline dissolutions occasions precipitations: but no differences, or not with sufficient uniformity to afford criteria, were observed according to the observations of other experimenters. strong solu 4. Concentrated aqueous solutions of various neutral tions of neu- salts, viz. muriate of ammonia; nitrate of potash; muriate tral salts, of soda; sulphate of soda, &c.; being mixed in due quantity with pus of the kinds under examination, produce viscidity, like ropy expectorated matter, thickening like jelly, and less opacity. These changes have, in the case of muri ate of ammonia, been called coagulation by Mr. Hunter; but by agitation in cold water the matters are diffused, and on standing, the pus is precipitated in its original state. I call these effects of the neutral salts inspissation, seemingly occasioned by their attracting water from the pus; for no such |
