Clinical diagnosis : the bacteriological, chemical, and microscopical evidence of disease / by Rudolf v. Jaksch ; translated from the second German edition by James Cagney ; with an appendix by Wm. Stirling.

Cagney James.

Date:: 1890

Credit: Clinical diagnosis : the bacteriological, chemical, and microscopical evidence of disease / by Rudolf v. Jaksch ; translated from the second German edition by James Cagney ; with an appendix by Wm. Stirling. Source: Wellcome Collection.

Provider: This material has been provided by the Royal College of Physicians of Edinburgh. The original may be consulted at the Royal College of Physicians of Edinburgh.

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$at birtli, falls gradually during the first few years of life, and reaches its lowest point in man at 35—45 y^i^rs of age. [It is diminished by hunger, in pregnancy, by the ingestion of solid or liquid food, or by gentle e.xercise.^®] To estimate the specific gravity of the blood, Roy's method may be adopted. This requires a series of test-tubes, holding a mixture of glycerine and water in different proportions, so that the sp. gr. of these shall range between 1.040 and 1.080. Some twenty test-tubes will bo needed, and each should hold 30-40 cc. The mixtures may best be prepared in the following manner:—Two graduated burettes are filled,—one with water and the other with glycerine,—and from each of these a certain quantity of glycerine and water, varying in a uniform manner, is poured into the above-mentioned test-tubes, the total quantity of the mixture being always 25 cc. Thus, in the first is placed 24 cc. water and i cc. glycerine; in the second, 23 cc. water and 2 cc. glycerine, and so on. In this way is obtained a series of fluids of uniformly varying sp. gr., as may be shown by the hydrometer. Into the fluid in each test-tube is now let fall a drop of blood, which will remain suspended in one of them, neither sinking nor rising; the specific gravity of this mixture is that of the blood. Very good approximate results may be obtained by this somewhat tedious process. [Instead of glycerine in this experiment, Landois employs solutions of sodic sulphate ranging between i.050-1.070 sp. gr., and the blood drawn from the finger is taken up in a capillary tube and expressed beneath the surface of the fluid. (See Appendix II.)] IV. CHANGES IN THE FORMED ELEMENTS OF THE BLOOD.— It is well known that the blood contains red and white corpuscles, and recent obseiwations {Bizzozero) have shown the presence in it of a third class of formed elements,—the blood-tablets (or blood-plates). The exi-stence of these bodies is now be}ond dispute. To make them apparent in fresh blood, it is necessary to fix the latter by the addition of some preserving fluid, such as HayemJs solution, when it may be examined directly with an oil-immersion lens and a narrow diaphragm. (See Appendix III.). The constitution of Hayem's sohdion is as follows:— 1 grm. of chloride of sodium, 5 grras. of sodic sulphate, 0.5 grin, corrosive sublimate, and 200 grms. distilled water. The preparation will then show the bodies in question as minute objects with a diameter less than half that of the red blood-corpuscles, scattered singly, or in groups in the field. In the present state of our knowledge, they possess no diagnostic importance. [They are sup-$