ITS PHYSICAL, CHEMICAL, AND STRUCTURAL CHARACTERS. 257 



the red corpuscles by the employment of an animal or a vegetable regimen, 

 but can make little or no impression upon the fibrin. 1 



191. The effects of Loss of Blood and of Abstinence are very similar in 

 their nature. Almost as soon as the stream begins to flow from a wounded 

 vessel, there seems to be a transudation of watery fluid from the tissues into 

 the current of blood; for this undergoes a rapid diminution in density, so 

 that the portion last drawn is of lower specific gravity, and contains a con- 

 siderably smaller amount of solid matter, than that which first issued. The 

 principal diminution occurs in the proportion of red corpuscles; the amount 

 of fibrin, albumen, extractive and saline matters and fat being only slightly 

 affected. 2 We shall find, indeed, that in inflammatory diseases the amount 

 of fibrin undergoes an extraordinary increase, which is not checked in the 

 slightest appreciable degree by the most copious venesection. It is remark- 

 able that after very considerable losses of blood, a decided increase shows 

 itself in the proportion of Colorless corpuscles, not only relatively (as to the 

 red) but absolutely; so that, in the blood of a Horse from which 50 Ibs. had 

 been previously abstracted, the colored and the colorless corpuscles appear 

 to exist in equal numbers. 3 



192. We have now to consider the differences which present themselves in 

 the composition of the Blood drawn from different vessels of the same body ; 

 these, it is obvious, being dependent on the changes to which the fluid is 

 subjected, during its passage through organs that will appropriate or change 

 its several constituents in an unequal degree. And the first and most im- 

 portant of these sets of differences, is that which exists between Arterial and 



Venous blood. The analyses already cited having been made chiefly upon 

 the latter, it will be sufficient here to state the general results of compara- 

 tive inquiries into the composition of the former. The quantity of solid 

 constituents pertaining to the Corpuscles is smaller; they contain relatively 

 more ruTemoglobiu and salts, but much less fat. The liquor sanguiuis is 

 somewhat richer in Fibrin; but it contains a larger proportion of water, and 

 consequently less Albumen. The Fatty matters of the serum, as well as of 

 the corpuscles, are considerably diminished; on the other hand, the Extrac- 

 tive and Saccharine matters are decidedly increased. The most remarkable 

 difference between Arterial and Venous blood, however, lies in the amount 

 of gases which they respectively contain. The observations of M. Malassez 4 

 have shown that the relative amount of corpuscles in the blood varies con- 

 siderably in different parts of the body, being really increased in the blood 

 of the splenic vein, because new corpuscles are formed in the spleen and 

 really diminished in the blood of the hepatic vein, owing to the destruction 

 of the corpuscles in the liver. On the other hand, they are apparently di- 

 minished in the meseuteric veins during digestion owing to the absorption 

 of fluid, and apparently increased in the blood returning from the skin, 

 glands and tissues generally owing to the exosmose of the fluid parts. 



193. Pneumatology of the Blood. The Gases contained in the blood prin- 

 cipally consist of Oxygen and Carbonic acid, the former being chiefly com- 

 bined with the red corpuscles, the latter wholly with the saline constituents 



1 See on this subject the treatise of M. Emile Marcband, De 1'Influence compara- 

 tive du Regime Vegetal et du Regime Animal sur Ic Physique et le Moral de 

 1 'Horn me. 



2 See the Observations and Analyses of Zimmerman (Heller's Archiv, Bd. iv, p. 

 385) ; Polli (Med.-Cbir. Review, Oct. 1847) ; J. Davy ( Anat. and Physiol. Researches, 

 vol. ii, p. 28). 



3 Kolliker's Manual of Human Histology (Sydenham Society's edit.), vol. ii, p. 

 330. 



4 See Pamphlet, 1873, and London Med. Record, 1874, p. 132. 



