iCTION OF FLUIDS ON THE BED CORPUSCLES 133 



discs with a faint yellowish color, figure no. Here and there white granular 

 cells of irregular outline will be noted, the white corpuscles. Examine the 

 drop of blood with a high magnifying power and sketch the outline of the 

 blood cells. Select the white corpuscle which is most irregular in outline 

 and make a series of outline drawings once every minute to show its ame- 

 boid movements, figure 117. 



Draw a drop of your own blood by puncturing the tip of the finger, under 

 sterile conditions, and mount in a drop of 0.9 per cent physiological saline. 

 Examine with a high power, note the small biconcave red corpuscles which 

 appear faintly yellow in color and even adhere in rouleaux, figure 109. The 

 white corpuscles will appear as somewhat larger granular discs differing in 

 form and size. By mounting a drop of blood on a warm stage the ameboid 

 movements of the white corpuscles can be observed with comparative ease. 



2. Action of Fluids on the Red Corpuscles. Water. When water is 

 added gradually to frog's blood, the oval disc-shaped corpuscles become 

 spherical and gradually discharge their hemoglobin, a pale, transparent 

 stroma being left behind. Human red blood cells change from a discoidal 



o 





FIG. 126. FIG. 127. FIG. 128. FIG. 129. 



FIG. 126. Effect of Hypertonic Salt-Solution on the Red Blood-Corpuscles of Man. 

 FIG. 127. Effect of Acetic Acid. FIG. 128. Effect of Tannin. FIG. 129. Effect of Boric Acid. 



to a spheroidal form and discharge their cell-contents, becoming quite trans- 

 parent and all but invisible (ghost corpuscles). 



Hypertonic Salt-Solutions. Mount a drop of human blood in 2 per cent 

 sodium-chloride solution. The red blood cells lose their disc shape and be- 

 come sp*herical with spinous projections or crenations, figure 126. 



The original form of the red blood cells can be restored by transferring 

 them to isotonic salt-solution. 



Dilute Acetic Acid. This reagent causes the nucleus of the red blood 

 cells in the frog to become more clearly defined; if the action is prolonged, 

 the nucleus becomes strongly granulated, and all the coloring matter seems 

 to be concentrated in it, the surrounding cell-substance and outline of the 

 cell becoming almost invisible; after a time the cells lose their color altogether. 

 The cells in figure 127 represent the successive stages of the change. A 

 similar loss of color occurs in the red cells of human blood, which, from the 

 absence of nuclei, seem to disappear entirely. 



Alkalies. Alkalies cause the red blood-corpuscles to absorb water and 

 finally to disintegrate, 



