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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$IL Fats (0-1 to 0-2 per cent.).—Neutral fats (tristearin, tripalmitin, triolein) occur in the blood in the form of small microscopic granules, which, after a meal rich in fat (or milk), render the serum quite inilky. [The amount of fat in the serum of fasting animals is about 0'2 per cent.; during digestion 0-4 to O-Q per cent.; and in dogs fed on a diet rich in fat it may be 1-25 per cent. °There are also minute traces of/«% acids (succinic). Röhrig showed that soluble soaps, i.e., alkaline salts of the fatty acids, cannot exist in the blood. Cholesterin may be considered along with the fats. It occurs in considerable amount in nerve-tissues, and, like fats, is extracted by ether from the dry residue of blood-serum. Hoppe-Seyler found 0-019 to 0-314 per cent, in the serum of the blood of fattened geese. There is no fat in the red blood-coriniscles. Lecithin (its de- composition-products, glycerin-phosphoric acid and protagon) occur in serum and also in the blood-corpuscles. ] III. Traces of Grape-Sugar [0 1 to 0-15 per cent, (more in the hepatic vein, 0-23 per cent.)] derived from the liver and muscles, and increased after hfemorrhage (§ l'J'5); some glycogen, and another reducing fermentative substance. The amount of grape-sugar in the blood increases with the absorption of sugar from the in- testine, and this increase is most obvious in the blood of the portal and hepatic veins ; there is also a slight increase in the arterial blood, but there it is rapidly changed. The presence of sugar is ascertained by coagulating blood by boiling it with sodium sulphate, pressinc^ out the fluid, and testing it for sugar with Fehling's solution {01. Bernard). Pavy coaffulates the blood with alcohol. IV. Extractives.—Kreatin, urea (0-016 percent, increased after nitrogenous food), succinic acid, and uric acid (more abundant in gouty conditions), guanin (?), carbamic acid, sarcolactic acid, all occur in very small amounts. V. Salts (0-85 per cent.), especially socUc chloride (O'ö per cent.) and sodic car- bonate. [It is most important to note that the soda salts are far more abundant in the serum than the potassium salts. The ratio may be as high as 10 : 1.] Animal diet increases the amount of salts, vegetable food diminishes it tempo- rarily. Salts in human blood-serum {Hoi)pe-Seijler). Sodic Chloride, . . 4-92 per ioOO ,, Sulphate, , 0-44 Carbonate, . 0-21 Sodic Phosphate, . 0-15 per 1000 Calcic Phosphate, . 1 ^ »70 Magnesic ,, _ |0-73 If large quantities of salts are introduced into the blood, they almost entirely disappear from the blood-stream withm a few minutes, chiefly by diff^usion into the tissues. They are graduallv eliminated by the kidneys. The same is true of sugar and peptones {Ludwig and Klicowicz). VI. Water about 90 per cent. VII. A yellow pigment. The pigment may be extracted with methylic alcohol. It shows two absorption-bands of a hpochronie hke lutein {Krukenherg). Thudichum regards the pigment of the serum as lutein ; Maiy, as hydrobilirubm ; and MacMunn as choletelin. [Poisonous Blood-serum.-The blood-serum of the following genera of fishes-Ano-uilla Muraena and Conger—acts as apowerful poison. Mosso calls the poisonous substanceichthitoxin' A dose of 0-02 c.c. per kilogramme weight of a dog is fatal. The action of this body is analo- gous to that of snake-poison.] ^ 33 THE GASES OF THE BLOOD.-Absorption by SoM Bodies.-A considerable attraction exists between the particles of solid porous bodies and gases, whereby the latterare attracted and condensed withm the pores of solid bodies, i.e., the gases 2.Ye absorbed. Thus, 1 volume of boxwood^charcoal (at 12° C, and ordinary barometric pressure) absorbs 35 volumes CO, 9-4 vol. U vol. N 1-75 vol. H. Heat is always formed when gases are absorbed, and the aniount of heat evolved bears a relation to the energy with which the absorption takes place. W on-porous bodies are similarly invested by a layer of condensed gases on their surface. uy itiuia^.—Mmds can also absorb gases. A known quantity of fluid at different pressures always absorbs the same volume of gets. Whether the pressure be great or small, the volume of W f?«7^r equally great ( W. Henry). But according to Boyle (1662) and Marriotte's (lö79) on the compression of gases, when the pressure within the same voluvie of gas is in- ' ,1! ''^7''' T'' inversely as the pressure. Hence it follows that, with varying pressure, the volume of gas absorbed remains the same, but the quantity of gas [iceight) is$