HUMAN LEUKOCYTES, SHOWING AMEBOID MOVEMENTS. 



47 



If, therefore, colonies of staphylococcus (bacteria of suppuration) collect at a given 

 part of the body their metabolic products attract the leukocytes from the neighbor- 

 ing vessels, and in this way inflammatory reaction and suppuration result. The 

 poison is either eliminated with the pus or is destroyed by the phagocytic activity 

 of the leukocytes. The leukocytes also secrete special chemical substances that 

 destroy the injurious microorganisms. These substances are known as alexins. 



In warm-blooded animals the leukocytes exhibit movement for a 

 long time upon a warm stage at a temperature of 40 C. for about two 

 or three hours; a temperature of 47 C. induces rigidity: heat-rigidity 

 and death. The lowest degree of temperature at which ameboid move- 

 ment is possible is 14 C. In cold-blooded animals, such as the frog 

 the leukocytes can be seen to make their way out of a small coagulated 

 blood-clot in a moist 

 chamber and move 

 about in the express- 

 ed serum, v. Reck- 

 linghausen observed 

 motile phenomena on 

 the part of leukocytes 

 in a moist chamber 

 for as long as three 

 w r eeks. Oxygen is 

 necessary for the 

 moA r ement. Induc- 

 tion-currents cause 

 the leukocytes sud- 

 denly to become 

 round, like irritated 

 amebae through re- 

 traction of all of 

 their processes. If the electric current be not too strong, the leuko- 

 cytes resume their movements in the course of a short time. Strong 

 and long-continued currents destroy them, causing them further to swell 

 and undergo complete disintegration. The dissolution of white blood- 

 corpuscles is known as leukocytolysis . It occurs as a normal phenom- 

 enon in the circulating lymph and in the blood in limited degree. 



With regard to the -source and the functional significance' of the different 

 varieties of leukocytes complete knowledge is as yet wanting. An attempt has 

 been made to obtain a sharper differentiation of the leukocytes through the 

 property of the smallest granules within the protoplasm of the cells to stain only 

 with acid or with basic or with neutral pigments. 



Method. Recently shed blood is spread in a thin layer upon a cover-slip, 

 dried in the air, then placed in an air-bath at a temperature of i25C. for two hours. 

 Next it is stained, washed with water, dried in the air and enclosed in Canada 

 balsam. 



The granules of the oxyphile or eosinophile cells (Fig. 8, a,b, with unstained 

 nucleus; "in c the nucleus is stained violet with hematoxylon) are stained only 

 by acid pigments, such as a saturated solution of eosin in 5 per cent, carbolglycerin. 

 The source of these cells is the bone-marrow. In normal human blood they con- 

 stitute only about 10 per cent, of all of the leukocytes, but in cases of leukemia 

 they pass in large number from the bone-marrow into the blood-stream -myel- 

 ogenous leukemia. 



The fine granules of the large mononuclear cells of normal blood are stained 

 only by basic pigments, such as a concentrated watery solution of methylene-blue 

 (f, g), as well as those of the majority in lymphemic blood. The cells known as 

 mast-cells contain basophile granules of other size (d, e). These cells are rare in 

 normal blood, but they often occur in large number in leukemic blood. Mast- 



FIG. 7. Human Leukocytes, Showing Ameboid Movements. 



