432 SECOND CLASS OF MINERAL CONSTITUENTS. 



inflammatory attack gives occasion for the abstraction of blood. 

 We shall return to this subject more fully in the second volume, 

 when considering " The Blood." 



Even if the well known action of chloride of sodium on the 

 colour of the blood be entirely dependent on mechanical relations, 

 the occurrence of almost constant quantities of this salt in the 

 blood during health, and its considerable variations in different 

 diseases, and, further, its chemical action on histogenetic sub- 

 stances, indicate that in all probability it takes some definite che- 

 mical part in the metamorphosis of the blood. Hofmann* believes 

 that it increases the capacity of the constituents of the blood for 

 oxidation, which however, requires proof. 



Berzelius was formerly of opinion that the quantity of albumen 

 contained in the serum of the blood might be the cause why the 

 blood-pigment which is so readily soluble in pure water did not 

 dissolve in the serum, but Joh. Muller has shown that the capsules 

 of the blood-corpuscles dissolve, if they are brought in contact 

 with an aqueous and not too dilute solution of albumen ; if, how- 

 ever, we treat the albumen with a little water containing only l- of 

 chloride of sodium, the corpuscles remain unchanged, whereas they 

 are destroyed by a pure solution of salt containing no albumen. 



We shall treat, at some length, of the mode of action of chloride 

 of sodium and various other bodies on the red colour of the blood, 

 in the second volume. It is here sufficient to remark that Scherer's 

 experiments have clearly demonstrated that the bright or dark 

 colour of the blood principally depends on the form of the blood- 

 corpuscles, which again is chiefly dependent on the endosrnotic 

 relations existing between their contents and the surrounding fluid. 

 For instance, if we add much salt to blood, the corpuscles become 

 contracted and biconcave ; it is to this biconcave form that Scherer 

 attributes the brighter colour of the blood. 



In those fluids which are secreted from the blood and which 

 contain a larger quantity of chloride of sodium than the blood 

 itself, as, for instance, the saliva, gastric juice, inflammatory 

 exudations, pus, and mucus, this salt doubtless discharges some 

 important functions. We claim no high importance for it in the 

 saliva; but if that fluid exercises a function, the chloride of sodium 

 certainly takes part therein, since its quantity exceeds that of all 

 he other constituents of the saliva. In the gastric juice 

 we find, in addition to a little organic matter, scarcely any- 

 thing but metallic chlorides, and chiefly chloride of sodium. 

 * Das Protein u. s. w. S. 19. 



