208 



VETERINAKY PHYSIOLOGY 



activity of the bone marrow is increased in certain patho- 

 logical conditions. 



These various forms have certain properties (a) Amoeboid 

 movement. They can, under suitable conditions, undergo 

 certain changes in shape, as may be readily seen in the blood of 

 the frog or other cold-blooded animal. The motion may consist 

 simply of the pushing out and withdrawal of one or more 

 processes (pseudopodia), or, after a process is extended, the 

 whole corpuscle may follow it and thus change its place, or 

 the corpuscle may simply retract itself into a spherical mass. 

 As a result of these movements the corpuscles, in certain con- 



a 



FIG. 102. Cells of the Blood, a, erythrocytes ; b, large, and c, small lym- 

 phocyte ; d, polymorpho-uuclear leucocyte ; , eosinophil leucocyte. 



ditions, creep out of the blood vessels and wander into the 

 tissues (Diapedesis). 



(b) Phagocyte action. The finely granular leucocytes and 

 the lymphocytes have further the power of taking foreign 

 matter into their interior, and of thus digesting it. By this 

 devouring action, useless and effete tissues are removed and 

 dead micro-organisms in the body are taken up and got rid of. 

 This scavenger action of the leucocytes is of vast importance in 

 pathology. 



Chemistry of Leucocytes. The nucleus is chiefly made up of 

 nuclein, and in the protoplasm a nucleo-protein, along with 

 two globulins and a small amount of an albumin, are found. 

 Along with these protein substances glycogen and a small 



