THE BLOOD. 



215 



FIG. 46. 



their coloring matter, a special change in their form is exhibited. 

 Their thick edges, absorbing water more abundantly than the rest, 

 become turgid, and encroach gradually on the central part. The 

 central depression, under these circumstances, may disappear on one 

 side before it is lost on the other, so that the globule, as it swells 

 up, curls over laterally, and assumes a cup-shaped form. (Fig. 46, 

 a, a.) This may often be seen in blood-globules after soaking for 

 some time in the urine, or other animal fluids of less density than 

 the plasma of the blood. Dilute acetic acid at once extracts the color- 

 ing matter of the globules, reducing them to the condition of pale and 

 nearly invisible colorless bodies, which, however, remain for a long 

 time, and are dissolved very 

 slowly in comparison with the 

 coloring matter. 



Dilute alkaline solutions, on 

 the contrary, readily dissolve 

 the whole substance of the 

 blood-globules. A solution of 

 potassium hydrate, in the pro- 

 portion of ten per cent., acts 

 most rapidly in this ^manner. 

 Solutions of soda and ammonia 

 have a similar effect, though 

 less promptly than the preced- 

 ing- 

 Solutions of sodium glyco- 

 cholate or taurocholate, in any 

 grade of concentration, or of the 

 fresh bile itself, as shown by 

 Ku'hne, also dissolve the red globules of the blood. 



Composition of the Red Globules. The red globules are composed 

 of an albuminous and a coloring matter, with mineral salts and water. 

 According to Lehmann, the water of the red globules amounts to 688 

 per thousand parts ; a little over 8 parts per thousand consisting of 

 mineral salts, namely, sodium and potassium chlorides, phosphates, and 

 sulphates, together with lime and magnesium phosphates. 



The most important ingredient of the red globules is their coloring 

 matter, or hemoglobine. According to the estimates of Preyer,* founded 

 on the observed quantity of iron as an ingredient, the average pro- 

 portion of hemoglobine in human blood is 12.34 per cent. As the 

 globules constitute 45 per cent, of the entire blood, the quantity of 

 hemoglobine in each globule is about 27 per cent, of its mass, or 86 per 

 cent, of its solid ingredients. It is accordingly the principal substance 

 of which the globules are composed. 



In the fresh globule the hemoglobine is united with a colorless albu- 



RED GLOBULES OF BLOOD, after the imbibition 

 of water. 



Die Blutkrystalle. Jenu, 1871, p. 117. 



