150 



THE BLOOD 



By this method it has been found that the weight of the corpuscles in 

 100 g. of defibrinated blood is 48 g. (mean of nine observations) for the man 

 and 35 g. (mean of eleven observations) for the woman. 



The red blood corpuscles are continually going to pieces in the body in 

 great numbers, especially, as it appears, in the liver. Naturally there is, 

 under normal conditions, a corresponding production of new ones. In em- 

 bryonic life the liver and spleen play a prominent part in their formation. 

 In the adult, according to most authors, red blood corpuscles are formed only 

 in the red marrow of the bones. (For the importance of Fe in the formation 

 of haemoglobin, see Chapter VIII.) 



The blood corpuscles owe their red color to the pigment substance haemo- 

 globin, whose chemical properties were first closely investigated by Hoppe- 



Seyler. It unites with oxygen into a 

 compound called oxyhcemoglobin, the 

 amount of which depends (to some ex- 

 tent) upon the partial pressure of the 

 available oxygen. The haemoglobin in 

 the arterial blood occurs chiefly in this 

 form; in venous blood haemoglobin as 

 well as oxyhaemoglobin is found; but in 

 asphyxiated blood only hemoglobin. 



By thinning with water, by repeated 

 freezing and thawing, by addition of 

 ether, chloroform or bile, or of acids or 

 bases, the coloring matter may be washed 

 out of the corpuscles and brought into 

 solution. The blood is then said to be 

 of a laky color, or is lake d. In many 

 cases the passage of the haemoglobin out 

 of the corpuscle does not run parallel to 

 the outward diffusion of the electrolytes. 



Under certain circumstances the haemoglobin passes out while the electrolytes 

 remain behind. Under others the opposite takes place: the electrolytes leave 

 the corpuscle and the haemoglobin remains. This shows that the mode of 

 combination of the haemoglobin and of the electrolytes is somewhat different 

 (Stewart). 



According to Hoppe-Seyler neither the haemoglobin nor the oxyhaemoglobin 

 is present as such in the red corpuscle, but as a tolerably firm combination 

 with another substance, probably lecithin. The combination which contains 

 oxyhaemoglobin is called arterin, while that of which, haemoglobin is a con- 

 stituent is known as phlebin. 



After the coloring matter is dissolved out of the red blood corpuscles there 

 remains a colorless mass called the stroma. This consists of lecithin, choles- 

 terin, proteids, urea, and mineral substances, chiefly potassium, phosphoric 

 acid and chlorine, and in the red blood corpuscles of man, sodium. 



By far the greatest part (eighty-seven to ninety- five per cent) of the dry 

 substance of the red blood corpuscle consists of haemoglobin: the stroma of 

 the blood corpuscles amounts therefore to only five to thirteen per cent. In 



FIG. 46. Blood crystals, after Funke. 

 a, from the human blood; 6, from the 

 blood of the guinea pig; c, from the 

 blood of a squirrel. 



