234: OF THE BLOOD: 



blood which has the lowest temperature under ordinary circumstances is that 

 which has circulated through the cutaneous capillaries, where it has been 

 exposed to the cooling influences of evaporation and radiation ; though Ber- 

 nard ascertained that on carefully enveloping the head or limbs of an animal 

 in cotton-wool, the temperature of the arterial and venous blood in the large 

 vessels soon becomes equalized. The blood of the left ventricle again is, for 

 similar reasons, generally * of a lower temperature than that of the right. 

 The highest temperature is attained in passing through the glands, muscles, 

 and nerves ; for in all such parts, especially during the active performance 

 of their functions, energetic processes of oxidation are being carried on. 

 Hence the blood of the Vena Portse, which has traversed the capillaries of 

 the intestines, spleen, etc., is warmer, especially during digestion, than even 

 the arterial blood ; and the blood which possesses the highest temperature in 

 the body, and which is frequently 2 or 3 F. above the ordinary venous 

 blood is that of the Hepatic Vein, which has been subjected to the active 

 assimilative operation of the liver. The specific heat of the blood of the 

 Ox is on the average 1.02. 2 When we add that the Blood has a saltish taste, 

 and a faint odor resembling that of the pulmonary and cutaneous exhalations 

 of the animal from which it is drawn, we have enumerated all the charac- 

 teristics which can be made out by the unassisted senses. 



172. When the Blood is examined with the Microscope, either immedi- 

 ately upon being drawn, or whilst it is yet circulating in the vessels of the 

 living body (as in the tongue or foot of the Frog, the wing of the Bat, the 

 omentum of the Guinea-pig, 3 or any other membranous expansion of similar 

 transparency), it is seen that its apparent homogeneity is not real, but that 

 it consists of two very different components. These are a transparent and 

 perfectly colorless liquid which is known as the Liquor Saiiyi/inis, and a set 

 of Corpuscles which are suspended in it: the great mass of these last present 

 a distinctly red hue, and it is to their presence alone that the color of the 

 blood is due; but there are also to be seen, scattered among the red, a few 

 which are colorless, and which differ from the red in some other particulars 

 presently to be noticed. On the other hand, when the Blood has been drawn 

 from the body, and is allowed to remain at rest, it undergoes at ordinary 

 temperatures spontaneous coagulation, in the course of which it separates 

 into a red Crassamentum, and a nearly colorless Serum. The "crassamen- 

 tum" or "clot" is composed of a network of Fibrin, presenting a more or 

 less distinct fibrous texture; in the meshes of which the Corpuscles, both red 

 and colorless, are involved, together with a certain amount of serous fluid. 

 The "serum," which is the same with the "liquor sanguiuis " deprived of 

 its fibrin, coagulates by heat, and is therefore known to contain Albumen ; 

 and if it be exposed to a high temperature sufficient to decompose the ani- 

 mal matter, a considerable amount of earthy and alkaline Salts remains. 

 Thus we have four principal components in the Blood; namely, Fibrin, Al- 



1 Sec tin 1 variable results obtained in Colin's experiments, recorded in the Ann. d. 

 Sci. Nat., Ser. v, t. vii, 18G7, p. 83. Jacobson and Bernhardt found tlie temperature 

 of tin- Left Heart to be from "0.1 2 to 0.42 Cent, warmer than the Right, as ascer- 

 tained l>y the introduction of a compound needle connected with a iherruometric 

 apparatus through tin- parietos of the chest into the cavity of the ventricles (see (Vn- 

 tralblatt, 1868, p. G89)." Korner, however (Inaug. Dissert., Breslau, 1871), and 

 Ileidcnhain ( I'll liter's Archiv, Bd. iv, 558) support Bernard's statements. Albert 

 and Strieker (Strieker's Jahrbiicher, 1873, p. 12'.)) found a thermometer inserted into 

 the xu/iNtniicr of the muscular tissue of the left ventricle, stood 0.5-0.7 Cent, higher 

 than when introduced into the cavity of the same ventricle in the living animal, which 

 may in part explain the discrepancy in the different experiments. 



2 Garngce, Journ. of Anat. and Physiol., vol. ii, p. 139. 



3 See Burdon Sanderson, Handbook for the Physiological Laboratory, 1873, p. 231. 



