206 CIRCULATING FLUIDS: 



proportions of fat in arterial and venous blood amounted to only 

 •92^ and -SSIJ respectively. Hence it appears (and in this re- 

 spect my own observations confirm those of Schultz) that this 

 blood contains a larger proportion of fat than either arterial or 

 venous blood. The albumen and the clot contain individually 

 a larger quantity of fat in this than in ordinary blood. Schultz 

 has observed a very striking difference between the quantity of 

 fat contained in the fibrin of this and of arterial blood : the 

 former yielded 10-72, while the latter gave only 2'34<g of fat, 

 which in the first case was brown and discoloured, in the latter 

 was Avhite and crystalline. 



It follows from these remarks that there is no constancy in 

 the deviations of the blood of the vena portai from arterial or 

 venous blood. The reason of the mutability of the composition 

 of this blood is easily accounted for, if we consider the relation 

 that the ramifications of the vena portse bear to the digestive 

 organs, and the absorbent power of the veins, as shown by the 

 experiments of Magendie,i Tiedemann, and Gmelin.^ 



The rapid removal of water from the stomach can, moreover^ 

 only be explained by the agency of the vena portae. 



Hence it is evident, both from my own analyses and those 

 of Schultz, that the blood which is conveyed to the hver by 

 the vena portse differs in well-fed and in fasting animals. 



When fluids, containing a smaller proportion of solid residue 

 than ordinary blood, are absorbed by well-fed animals, we may 

 naturally infer that the blood of the vena portee will be more 

 deficient in solid constituents than either arterial or venous 

 blood. This view is confirmed by the observations of Schultz, 

 excepting in the case of the horse that had been fed with oats 

 shortly before its death, when a greater solid residue was left 

 by this blood than by either the arterial or venous : in this in- 

 stance, however, the residue was below the ordinary average of 

 either venous or arterial blood. In fasting horses the residue 

 is considerably below the average of ordinary blood. 



The remarkably small quantity of fibrin that is invariably 

 found in the blood of the vena portae, as well as the large pro- 

 portion of fat that is associated Avith the fibrin, is a point of con- 

 siderable interest ; as also the large proportion of blood-corpuscles 



' Precis elementaire de Physiologic, par Magendie. Bruxelles, 1838, p. 328. 

 * Midler's Physiologic des Menschen, vol. 1, p. 241. 



