Volume 1

A text-book of human physiology : including histology and microscopical anatomy with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition with additions by William Stirling.

Landois, L. (Leonard), 1837-1902. Lehrbuch der Physiologie des Menschen. English

Date:: 1891

Credit: A text-book of human physiology : including histology and microscopical anatomy with special reference to the requirements of practical medicine / by L. Landois ; translated from the seventh German edition with additions by William Stirling. Source: Wellcome Collection.

43/602 page 3

$Clinical Method.—A thin glass tube is drawn out till it is of small calibre, and then bent at a right angle, and closed above with a caoutchouc cap, thus forming a small pipette. With this pipette, suck up a drop of freshly-drawn blood obtained by pricking the finger. The fine capillary-tube is at once immersed in a solution of sodic sulphate, and a drop of the blood expressed into the saline solution. It is necessary to prepare several solutions of sodic sulphate with specific gravities varying from 1050-1070. The solution in which the corpuscles remain suspended indicates the specific grav^ity of the blood {Roy, Laiidois). The drinking of water and hunger diminish the specific gravity temporarily, while thirst and the digestion of dry food raise it. If blood be passed through an organ artificially, its specific gravity rises in consequence of the absorption of dissolved matters and the giving off of water. It falls after htemorrhage, and is diminished in badly-nourished individuals. [By working with solutions of glycerine, Jones finds that it is the highest at birth, and at a minimun° between the second week and the second year ; it rises gradually until the 35th-45th year. It is usually higher in the male than the female, is diminished 'by pregnancy, the ingestion of solid or liquid food, and gentle exercise.] [(6) Temperature.—Blood is viscid, and its temi^erature varies from 36-5° C, (97-7° F,) to 37-8° (100° F,). The warmest blood in the body is that of the hepatic vein (§210).] 2. MICROSCOPIC EXAMINATION.—[Blood, when examined by the micro- scope, is seen to consist of an enormous number of corpuscles—coloured and colourless—floating in a transparent fluid, the plasma, or liquor sanguinis, together with the blood-plates or platelets.] /•^ ß Fig. 1. A, human coloured blood-corpuscles—1, on the flat; 2, on edge ; 3, rouleau of coloured cor- puscles. B, amphibian coloured blood-corpuscles—1, on the flat; 2, on edge. C, ideal transverse section of a human coloured blood-corpuscle magnified 5000 times linear—ao, diameter ; cd, thickness. I. Human Red Blood-Corpuscles.— (a) Form.—They are circular, coin-shaped, homogeneous discs, with saucer-Hke depressions on both surfaces, and with rounded margins; in other words, they are bi-concave, circular non-nucleated discs (figs. 1, A; 5). (6) Size.—The_ diameter (ah) is 7-7/>t,i (6-7-9-3/>t) the greatest thickness^(c^^) 1-9/x (fig. 1, C), [i.e., it is -^^-^ to of an inch in diameter, and 'aboutone- fourth of that in thickness]. They are slightly diminished in size by septic fever, inanition, morphia, increased bodily temperature, and QO.^, and increased by 0, watery condition of the blood, cold, consumption of alcohol, quinine, and hydrocyanic acid. Compare § 10, 2. If the total amount of blood in a man be taken at 4400 cubic centimetres, the corpuscles, ^ The Greek letter ii represents one-thousandth of a millimetre (^ = 0-001 mm.), and is the sign of a micro-millimetre, or a micron.$