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.

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    when the conl is tied at once, while if it is tied somewhat later it may be ^. Immediate ligature of the cord may, therefore, deprive a newly-boru child of 100 grams of blood. Further, the number of corpuscles is less in a child after immediate ligature of the umbilical cord than when it is tied somewhat later {Helot). The methods of Valentin (1838), and Ed. Weber (1850), are not now used, as the results obtained are not sullieiently accurate. Method of Welcker (1854).—Begin by taking the weight of the animal to be experimented on ; place a cannula in the carotid, and allow the blood to run into a llask previously weighed, and in which small pebbles (or Hg) have been placed in order to defibrinate the blood by shaking. Take a part of this detibrinated blood, and make it cherry-red in colour by passing tlirough it a stream of CO (because ordinary blood varies in colour according to the amount of 0 contained in it—Gschcidlcn, HcideiUmin). Tie a \— shaped cannula in the two cut ends of the carotid, and allow a 06 per cent, solution of common salt to flow into the vessel from a pressure bottle ; collect the coloured fluid issuing from the jugular veins and inferior vena cava until the fluid is ([uitc clear. The entire body is then chopped up (with the exception of the contents of the stomach and intestines, which are weighed, and their weight deducted from the body-weight), and extracted with water, and after tweutj'-four hours the fluid is expressed. This water, as well as the washings with salt solution, are collected and weighed, and part of the mixture is saturated with CO. A sample of this dilute blood is placed in a vessel with parallel sides (1 cm. a])art) opposite the light (the so-called hsematinometer), and in a second vessel of the same dimensions a sample of the undiluted CO blood is diluted with water from a burette, until both fluids give the same intcnsitii of colour. From the quantity of water required to dilute the blood to the tint of the washings of the blood-vessels, the (juantity of blood in the washings is calculated. On chopping up the muscles alone, we obtain the amount of Hb present in them, which is not taken into calculation. Quantity of Blood in Various Animals.—^The quantity of blood in the mouse - tV to tV ; guinea-pig (yV to J^); rabbit = to ^V) ; dog = ^ to ^g) ; cat = ^i.y ; birds = to y^y ; frog = to ; hshes = to of the body- weight (without the contents of the stomach and intestines). The specific gravity of the blood ought always to be taken when estimating the amount of blood. The amount of blood is diminished during inanition ; fat persons have relatively less blood ; after hiemorrhage the loss is at first replaced by a watery fluid, while the blooil-cor- puscles are gi-adually regenerated. Blood in Organs.—The estimation of the quantity of blood in different organs is dune by suddenly ligaturing their blood-vessels intra vitam. A watery extract of the chopped-up organ is prepared, and the quantity of blood estimated as described above. [Roughly it may be said that the lungs, heart, large arteries, and veins, contain |; the muscles of the skeleton, \ ; the liver, \ ; and other organs, \ {Ranke).\ 41. ABNORMAL CONDITIONS OF THE BLOOD.—(A) 1 Polysemia.—(1) An increase in the entire mass of the blood, uniformly in all organs, constitutes 7w/?/«7;ii'rt. or 2)lcthora, and in over- nourished individuals it may approach a pathological condition. A bluish-red colour of the skin, swollen veins, large arteries, hard full pulse, injection of the ca])illaries and smaller vessels of the visible mucous membranes are signs of this state, and, when accompanied by congestion of the brain, there is vertigo, congestion of the lungs, and breathlessness. After major amputations with little loss of blood a relative but transient increase of blood has been found (?) {plethora apoccptica). Transfusion.—Polyaimia may be jn-oduced artificially by the injection of blood of the same species. If the normal quantity of blood be increased 83 per cent, no abnormal condition occurs, because the blood-pressure is not permanently raised. The excess of blood is accommo- dated in the greatly distended capillaries, which may be stretched beyond their normal elasticity. If it be increased to 150 per cent, there are variations in the blood-pressiu-e, life is endangered' and there may be sudden rupture of blood-vessels ( Worm Miillcr). ' Fate of Transfused Blood.—After the transfusion of blood the formation of lymph is gi-eatly increased ; but in one or two days the serum is used up, the water is excreted chieHy^y the urine, and the albumin is partly changed into urea. Hence, the blood at this time appears to be relatively richer in blood-corpuscles {Famim, Lesser, Worm Miillcr). The red corpuscles break up much more slowly, and the products thereof are partly excreted as urea and partly (but not constantly) as bile-pigments. Even after a month an increase of coloured blood- corpuscles has been observed {Tschirjciv). That tlie blood-corpuscles are broken \m slowly iih the economy is proved by the fact, that the amount of lu-ea is much larger when the same quan- tity of blood is swallowed by the aiumal than when an equal amount is transfused {Tschirjeir. Landois). In the latter case there is a moderate increase of the urea, lasting for days, a proot'
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