A textbook of human physiology / translated from [the] 6th German edition by W. Stirling.

  • Landois, Leonard
Date:
1888
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Licence: Public Domain Mark

Credit: A textbook of human physiology / translated from [the] 6th German edition by W. Stirling. Source: Wellcome Collection.

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

    54/980 (page 2)
    tenipei-ature and the addition of an alkali favour the formation of the acid (iV. Zuntz). The idkaliiK; reaction of blood is diininishcd : (a) bj' groat nmscular exertion, owing to the tbrniatiou of a huge amount of acid in tlie nmsek'S ; (/8) during coaguhition ; (7) in old blood, or blood dissolved by water from old blood-stains, sueh blood being usually acid ; fresh cruor has a stronger alkaline reaction than serum ; (5) after the prolonged use of soda the alkalinity is increased, after the use of acids it is decreased. Methods.—Owing to the colour of the blood we cannot employ ordinary litmus jmper to test its reaction. One of the following methods may be used :—(1) Moisten a strip of glazed red litnuis paper with solution of common salt, and allow a drop of blood to fall on the paper ; then rapidly wipe it off before its colouring matter has time to penetrate and tinge the paper {Zantz). (2) Liebreich used thin plates of plaster-of-l'aris of a i)erfectly neutral reaction. These are dried, and afterwards moistened with a neutral solution of litmus. When a drop of blood is placed upon the ])orous plate, the Huid ])art of the blood ]iasses into it, while the corpuscles are washed off with water, and the altered colour of the litmus-stained slab is apparent. [(3) Schiifer uses drj' faintly-reddened glazed litmus jiaper, and on it is placed a drop of bloo(l, which is wiped olf after a few seconds. The place where the blood rested is indicated by a blue patch ujioii a red or violet ground.] Estimation of the Alkalinity.—A verj^ dilute solution of tartaric acid (1 cubic centimetre combines with 3'1 milligrams of soda, i.e., 1 litre of water contains 7'5 grams of crystallised tartaric acid) is added to blood until a blue litmus paper is turned red (by Zuntz's method). 100 grams of rabbit's blood have an alkalinity corresponding to 150 milligrams of soda ; the blood 6f carnivora to about 180 milligrams {La&snr), W'hile 100 c.c. of normal human Ijlood have an alkalinity eipial to 260-300 milligrams of soda (r. J((ksch). The following method can be used with a few drops of blood :—To neutralise the blood, tar- taric acid in the above concentration is used. Prepare the following jnixture by mixing it with a concentrated neutral solution of sodic sulphate, and then adding sodic sulphate until the nii.xture is comjdetely saturated. I., 10 parts of solution of tartaric acid to 100 ]iarts of con- centrated sodic sulphate solution ; H., 20 parts tartaric acid solution to 90 sodic sul[ihate solu- tion ; III. contains these substances in the proportion of 30 to 80 ; IV., 40 to 70 ; V., 50 to 60 ; VI., 60 to 50 ; VII., 70 to 40 ; VIII., 80 to 30 ; IX., 90 to 20 ; and X., 100 to 10. Excess of sodic sulphate is juesent in all the flasks. A known volume of the blood to be investigated is mixed with an eipial volume of each of the mixtures, in a small tube, which is maile by drawing out a glass tube 1 jnillimetre iu diameter to a fine point. To calibrate this tube, suck up water, say, to the height of 8 mm., make a mark on the tube w-ith a line file, then suck u}) the water initil its lower level corre- sponds with the mark. Again mark the upper limit of the water. To test the blood, suck ;v drop of the mixture I. up to the level of the first mark on the glass pipette, and, after wiping its point, suck up an eipial ([uantity of blood. Again clean the point of the pipette, and blow its contents into a watch-glass ; then mix, and test the reaction with sensitive violet-coloured litmus paper. Proceed in the same way with the several mixtures, II., to X., until the alkaline reaction disappears or the acid appears. The narrow strips of litmus jyaper are dipped into each of the mixtures, the corpuscles remain in the wetted part of the ])a}ier, while the tluid permeates further and shows the reaction. As a rule, the degree of alkalinity in human blood coiresponds to VI. Human blood can be sucked directly from a small wound made by a needle, either by attaching an elastic tube or a small hypodernuc syringe to the pipette- {Landois). Pathological.—The alkalinity is increased during persistent vomiting, and decreased in pronounced anajmia, cachexia, unemia, rheumatism, high lever, diabetes, and cholera. [Imme- diately before death by cholera it may be acid {Cantani).] (3) Odour.—Blood emits a peculiar odour, the halitus sanguinis, which diffei-s in animals and man. It depends upon the presence of volatile fatty acids. If concentrated sulphuric acid be added to blood, whereby the volatile fatty acids are set free from their combinations with alkalies, tht* characteristic odour, somewhat sinular to that of butyric acid, becomes much more perceptible. (4) Taste.—Blood has a saline taste, depending upon the salts dissolved in the fluid of the blood. (5) Specific Gravity.The specific gravity is 1056-1059 in man, 1051-1055 in woman; in children less. The specific gravity of the blood-corpuscles is 1105, that of the plasma 1027. Hence the corpuscles tend to sink. CHnical 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 ca^i. Press sligljtly on the caoutchouc cap and suck up a drop of the freshly-drawn blood obtained by piicking the finger. The fine capil-