GENERAL PROPERTIES: THE CORPUSCLES. 385 



blood to purplish red in venous blood, this variation in color being 

 dependent upon the amount of oxygen contained in the blood in 

 combination with the hemoglobin. Speaking generally, the func- 

 tion of the red corpuscles is to carry oxygen from the lungs to the 

 tissues. This function is, entirely dependent upon the presence of 

 hemoglobin, which has the power of combining easily with oxygen 

 gas. The physiology of the red corpuscles, therefore, is largely con- 

 tained in a description of the properties of hemoglobin. 



Condition of the Hemoglobin m the Corpuscle. The finer structure 

 of the red corpuscle is not completely known. It is usually stated 

 that the corpuscle is composed of two substances, stroma and hem- 

 oglobin, together with a certain amount of water and salts and 

 also small amounts of lecithin and cholesterin. The stroma is a 

 delicate, extensible, colorless substance that gives shape to the 

 corpuscles; it forms a meshwork or spongy mass in which the 

 hemoglobin is deposited. This latter substance forms the chief 

 constituent of the corpuscle, since it makes about 32 per cent, of the 

 weight of the normal corpuscle, and when dry from 90 to 95 per 

 cent, of the total solid material. The point that remains uncertain 

 is the condition in which the hemoglobin exists within the corpuscle. 

 It is evidently not in solution, since the amount present is too great 

 to be held in solution in the corpuscle, and, moreover even a thin 

 layer of corpuscles is far from being transparent. Nor is it deposited 

 in the form of crystals. It is assumed, therefore, that it is present 

 in a peculiar, amorphous form, and Gamgee has shown that from 

 its aqueous solutions the hemoglobin can be obtained in an amor- 

 phous state by the action of an electrical current. It is protected 

 from the action of the water, within and without the corpuscle. In 

 various ways, however, the relations of the hemoglobin within the 

 corpuscle may be disturbed; so that it escapes and enters into 

 solution in the plasma. Blood in which this has happened suffers 

 a change in color, becoming a dark crimson, and is therefore known 

 as "laked blood." Laked blood in thin layers is quite transparent 

 compared with the normal blood with its opaque corpuscles. 



Hemolysis. The act of discharging the hemoglobin from the 

 corpuscles so that it becomes dissolved in the plasma is designated 

 as hemolysis, and substances that cause this action are spoken of 

 as hemolytic agents. A number of such agents are known; but, 

 although the results of their action are the same, so far as the hemo- 

 globin is concerned, the way in which they bring about this result 

 must vary greatly. Some of the known methods of producing 

 hemolysis, or rendering the blood "laky," are as follows: (1) 

 By the addition of water to the blood or by diminishing in any way 

 the concentration or osmotic pressure in the plasma. (2) By add- 

 ing ether or chloroform. (3) By adding bile or solutions of the bile 

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