QUANTITATIVE ANALYSIS. 139 



following additional principles in the blood, which are either 

 constant or temporary constituents : Sugar, Fatty Emulsion, a 

 Coloring Matter peculiar to the serum, Urea, Uric Acid in 

 combination, Cholesterine, Creatine, and Creatinine. 



Sugar. Bernard l showed in 1848 that sugar always exists 

 in the blood of the hepatic veins and the right side of the 

 heart. It is manufactured by the liver, and disappears in the 

 lungs. When its production is most active, as in full diges- 

 tion, it may exist in small quantity in the arterial blood. 

 Ordinarily it is only to be found in the blood between the 

 liver and the lungs, except when it exists in the blood of the 

 portal vein, after the ingestion of saccharine Or starchy 

 matters. 



Fatty Emulsion. After a full meal with an abundance 

 of fat, the blood contains a considerable proportion of fatty 

 emulsion. Bernard 2 has shown, also, that the blood of the 

 hepatic veins contains an emulsive substance which is 

 formed by the liver. We have already seen that the blood 

 corpuscles contain a certain proportion of fatty matter in a 

 state of molecular union with the organic nitrogenized prin- 

 ciples. 



Coloring Matter of tlie Serum. The serum has a yellowish 

 color, more or less intense, which is dependent upon a pecu- 

 liar coloring matter. This has never been isolated, but is 

 thought by some to be identical with the coloring matter of 

 the bile, 3 a supposition, however, which does not seem very 

 probable. 



1 Recherches sur une Nouvelle Fonction du Foie considere comme Organe 

 Producteur de Matiere Sucree chez Fffomme et les Animaux. These. Paris, 

 1853. 



2 See page 64. 



8 BECQUEREL and RODIER, .Recherches sur la Composition du Sang dans 

 tetat de Sante el dans Vetat de Naladie, Paris, 1844. 



