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.

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$union between the HI) and 0, all the 0 of the blood can be expelled from its state of combination by those means which set free absorbed gases— (a) by introducing blood into a Torricellian vacuum. {h) by boiling. (c) by the conduction of other gases [H, N, CO, or NO] through the blood, because the oxyhsemoglobin compound is so loose that it is decomposed even by these physical means. Reducing Rsagents.—Amongst cliemical reagents the following reducinq substances—ammonium sulphide, sulphuretted hydrogen, alkaline solutions of sub- salts or Stokes's fluid, iron filings, &c., rob blood of its 0 (§ 15). Relation to Fe.—The amount of iron in the blood (0-55 in 1000 parts) stands in direct relation to the amount of Hb ; this to the quantit}' of blood-corpuscles ; and this, in turn, to the specific gravity of the blood. The amount of 0 in the blood, therefore, is nearly proportional to the specific gravity of the blood, and it is also in proportion to the amount of iron in the blood. The total amount of iron in the blood is about 3 grams. During morphia narcosis the amount of 0 in the blood is diminished {Ewald) ; after htemor- rliage the arterial blood is saturated with 0 (/. G. Ott). Disappearance of 0 in Shed Blood. —Even immediately after blood is shed there is a slight disappearance of 0, as a physiological index of respiration of the tissues within the living blood itself (§ 131). When blood is kept long outside of the blood-vessels, the quantity of 0 gradually diminishes, and if it be kept for a length of time at a high temperature it may disappear alto- gether. This depends upon decomposition occurring in the blood, whereby reducing substances are formed which consume the 0. All kinds of blood, however, do not act with equal energy in consuming 0, e.g., venous blood from active muscles acts most energetically, while that fro^i the hepatic vein has very little effect. CO2 appears in the blood in place of the 0, and the colour darkens. The aniount of CO2 produced is sometimes greater than that of the 0 consumed. Relation to Acids.—If blood (or a solution of oxyh^emoglobin) be acted upon by acids {e.g., tartaric acid) until it is strongly acid, 0 can be pumped out in considerably less amount, wdiile the formation of CO^ is not increased. We must therefore assume that, during the decomposi- tion of the Hb caused by the acids (§ 18), a decomposition product becomes more highly oxidised uy the intense chemical union of the 0 at the moment of its origin {Lothar Meyer, Ziintz, Strassburg). The same phenomenon occurs when oxyhsemoglobin is decomposed by 'hoiling. 37. IS OZONE PRESENT IN BLOOD ?—On account of the numerous and energetic oxidations which occur in connection with the blood, the question has often been raised as to whether the 0 of the blood exists in the form of ozone (Oo). Ozone, however, is contained neither in the blood itself (Schönbein) nor in the blood gases obtained from it. iS^evertheless, the red corpuscles (and Hb) have a distinct relation to ozone. (1) Tests for Ozone. —Htemoglobin acts as a conveyer of ozone, i.e., it is able to remove the active 0 of other bodies and to convey or transfer it at once to other easily oxidisable substances. {a) turpentine which has been exposed to the air for a long time always contains ozone. The tests for the latter are starch and potassium iodide, the ozone decomposing the iodide when the lodme strikes a blue with the starch, [h) Freshly-prepared tincture of guaiacum is also rendered blue by ozone. If some tincture of guaiacum be added to turpentine there is no reaction, but on adding a drop of blood a deep blue colour is immediately produced, i.e., blood takes the ozone troni the turpentine and conveys it at once to the dissolved guaiacum, which becomes blue It IS immaterial Avhether the Hb contains 0 or not. (2) It IS also asserted that hemoglobin acts as an ozone-producer, i.e., that it can convert the ordinary 0 of the aiv into ozone. Hence the reason why red blood-corpuscles alone render guaiacum blue. This reaction succeeds best when the guaiacum solution is allowed to dry on blotting-paper, and a few drops of blood (diluted 5 to 10 times) are poured on it. That the Hb torins ozone from the surrounding 0 is shown by the fact that red blood-corpuscles containing carbonic oxide cause the blue colour {Kühne and Scholz). According to Pflüger, however these reactions only occur from decomposition of the Hb, so that on this view the blood-corpuscles cannot be regarded as producers of ozone. Sulphuretted hydrogen is decomposed by blood (as by ozone itself) into sulphur and water, ilydric peroxide is decomposed by blood into 0 and water [but this reaction is prevented by the addition of a small amount of hydrocyanic acid {SchÖ7ibei7i)]. Crystallised Hb does not do this, and H2O2 may be cautiously injected into the blood-vessels of animals. This would show that unchanged Hb does not produce ozone. Various Forms of Oxygen.—There are three forms of oxygen :—(1) The ordinary oxygen (0.^)$