WHITE GLOBULES OF THE BLOOD. 



255 



Fig. 85. 



slippery than the red globules, and have a tendency to adhere more 

 readily to the surfaces with which they are in contact ; so that if a 

 small quantity of a watery fluid be added to the drop of blood under 

 examination, the red globules will be hurried away by the currents pro- 

 duced, while the white globules lag behind, and, if the irrigation be con- 

 tinued, may finally be left alone in the field of the microscope. Their 

 transparency is such that, when slowly rolling over with the current, 

 the granules in their interior may often be perceived to rotate past 

 each other, above and below, with the motion of the globule. The 

 nuclei are sometimes visible in the perfectly fresh globule, but may 

 always be brought into view by the addition of pure water or of dilute 

 acetic acid. The action of these fluids is to cause a slight swelling of 

 the globule and to increase the 

 transparency of its substance, 

 by which the nuclei become 

 perceptible as sharply defined 

 ovoid or vesicular bodies in or 

 near the central part of the 

 mass. By the prolonged ac- 

 tion of acetic acid, a portion 

 of the cell substance becomes 

 condensed about the nuclei in 

 various irregular forms, while 

 the remainder appears as a per- 

 fectly transparent and homo- 

 geneous material, surrounded 

 by a very delicate circular out- 

 line. The final effect of both 

 water and acetic acid is to dis- 

 integrate the white globules 

 and cause their disappearance. Dilute alkalies dissolve them with great 

 readiness. 



Amoeboid Movements of the White #Zo6u/es. These movements are 

 so called from their resemblance to the motions of Amoeba, a minute 

 gelatinous creature, of very simple organization, living in fresh-water 

 pools and ditches. They are never to be seen while the blood is circu- 

 lating in a normal manner within the bloodvessels, where the white 

 globules always present their natural rounded form and uniformly 

 granular appearance. But within a short time after the blood has been 

 withdrawn from the vessels, provided it be maintained at or near the 

 normal temperature of the animal, the white globules may be seen to 

 alter their shape in a very remarkable way. The first indication of the 

 change is that a certain portion of the rounded outline of the globule 

 becomes faint and irregular, its substance at this point flattening out 

 and extending itself into one or more transparent and homogeneous 

 looking prolongations. These prolongations are alternately protruded 

 and retracted, sometimes extending into long filamentous processes, 



WHITK GLOBULES OP THE BLOOD; altered 

 by dilute acetic acid. 



