344 THE BLOOD. 



An idea of the mineral constituents of the red corpuscles, viz., 

 their stroma, may be had from the following table, which is taken 

 from C. Schmidt, and calculated for 100 parts of the moist cor- 

 puscles. 



Potassium chloride 3.68 



Sodium chloride traces. 



Potassium sulphate 0.13 



Potassium phosphate 2.34 



Sodium phosphate 0.63 



Calcium phosphate 0.09 



Magnesium phosphate 0.06 



The iron of the haemoglobin is not included in this table ; in man 

 it varies between 0.506 and 0.537 pro mille. In addition traces of 

 copper are not infrequently met with, and, as will be seen later, this 

 element in some of the invertebrate animals apparently takes the 

 place of iron in the coloring-matter of the blood. 



Isolation of the Red Corpuscles of the Blood. To isolate the 

 red corpuscles, the blood is defibrinated by beating, diluted with ten 

 times its volume of a 1 per cent, solution of sodium chloride, and 

 passed through a muslin filter. On subsequent centrifugation and 

 repeated washing with the salt solution, they are then freed from the 

 serum, and may now be collected on a paper filter, after the previous 

 addition of a large amount of alcohol. Any fats, lecithins, or 

 cholesterins that may be present are extracted with warm alcohol 

 and ether, when the corpuscles can be dried and weighed. To 

 isolate the stromata, the mass of corpuscles, when freed from serum, 

 is shaken with five or six times its volume of water and a small 

 amount of ether. The mixture is then centrifugalized, and is thus 

 separated from the leucocytes. The stromata are now precipitated 

 by adding a few drops of a 1 per cent, solution of acid sodium 

 phosphate, until the liquid has almost assumed the consistence of 

 the original blood. They are then collected on a filter, quickly 

 washed with water, and may now be dissolved in a 5 per cent, solu- 

 tion of magnesium sulphate. 



Haemoglobin and Its Derivatives. 



Haemoglobin. The haemoglobin is the coloring-matter of the 

 red corpuscles, and is supposedly present in these in combination 

 with another body, which may be a lecithin, as thephlebin of Hoppe- 

 Seyler, while the corresponding compound of oxyhsemoglobin is 

 termed arterin. Of the nature of these compounds, however, 

 but little is known, and it has not even been definitely ascertained 

 that the pairling of the coloring-matter is really a lecithin. 



Hemoglobin or its oxy-compound occurs widely distributed in 

 the animal world, and is found not only in the vertebrates, but also 

 in many of the invertebrates. But while in the former it is con- 

 tained in definite cellular elements of the blood, it may also occur as 

 such among certain invertebrate animals. Closely related to it is 



