THE BLOOD. 181 



be seen slowly to alter their shapes and to send out from their cyto- 

 plasm little processes into which the remainder of the leucocytes 

 seem to flow, thereby causing a slight movement with change of 

 position. This process repeated successively gives to the cell its 

 power slowly to move from place to place, after having worked its 

 way through the vessel-walls into the surrounding connective tissues. 

 This locomotion is frequently termed the "wandering" of the cell. 



Fig. 53. Leucocytes of Man, showing Amoeboid Movement. (LANDOIS.) 



To their sticky exteriors there are frequently seen adhering 

 fine pieces of broken-down cells, bacteria, and other foreign par- 

 ticles. By reason of certain internal circulatory movements in the 

 protoplasm of the leucocytes, these adherent foreign particles may 

 be drawn into the interior of the cell, where some are digested, and 

 others excreted as effete matters. 



Functions of the Leucocytes. It is definitely known that the 

 leucocytes play an important role in the process of blood-coagula- 

 tion. Their relation to this most important process will be dis- 



