I04 INFECTIOUS AND PARASITIC DISEASES. 



The most important function of leucocytes 



in local and general inflammations is to 

 TOSIS. , , ? . ,.,.,. 



destroy bacteria, an action which is desig- 

 nated phagocytic J the function itself, phagocytosis. 

 In almost every inflammatory condition 

 of the body the number of leucocytes in 



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the blood is increased. Normally, there 

 are about 6000 of all kinds to the cubic centimeter, 

 but 50,000 to 60,000 are not unusual in inflammations. 

 When present in numbers above 7000, a leucocytosis 

 is said to be present. The explanation of this increase 

 of leucocytes in the blood is found in the large numbers 

 required at inflammatory foci. In the discharge 

 from an abscess, for example, there are present 4 to 5 

 millions per cubic centimeter. The additions made 

 to the normal number of leucocytes in the blood are 

 due to the stimulated activity of the blood-forming 

 (hematopoietic) organs which, as occasions arise, 

 verily surcharge the blood with them. Whence comes 

 the stimulus ? Obviously from absorption of a prod- 

 uct formed at the site of the injury. Leucocytosis 

 is therefore another phenomenon which should impress 

 upon us the deep-seated reactions occasioned by 

 every injury, whether the latter gives rise to general 

 symptoms or not, and how far parts of the defensive 

 mechanism are placed from the injury. In injuries 

 due to mechanical and physical agents, when not com- 

 plicated by invading bacteria, the succeeding inflam- 



