214 MANUAL OF BACTERIOLOGY. 



It is well known that a suppurating part contains large 

 numbers of leukocytes, and one of the most characteristic 

 events in the inflammatory process is the migration of leuko- 

 cytes to the point of irritation. This indicates a positive 

 chemotaxis for leukocytes on the part of substances in the in- 

 flamed area.' Metchnikofi believes that the function of 

 these leukocytes is to destroy the bacteria and to arrest their 

 further progress. On this theory bacteria have often been 

 likened to an invading army and the leukocytes or phagocytes 

 to a force designed to repel their attacks. 



It is certain that in some infectious diseases the number of 

 leukocytes, chiefly of the polynuclear neutrophilic variety, in 

 the circulating blood is increased (leukocytosis). This is the 

 case usually in lobar pneumonia and acute suppurative in- 

 fections. In some other infectious diseases there is usually 

 no leukocytosis; for example, tuberculosis, typhoid fever and 

 malaria. It is interesting to observe that in trichinosis, and 

 more rarely in infection with other animal parasites, the 

 eosinophihc leukocytes* become much more numerous in the 

 blood than normally. 



Manwaring and Rubj studied the effects of various anti- 

 septic and therapeutic agents upon phagocytosis, and found : 

 That carbolic acid causes diminution of phagocytosis in pro- 

 portion to the amount of carbolic acid present, causing complete 



* Williams and Bentz. Trans. Association of American Physicians. XVI] I. 

 1903. p. 152. 



Further References. 



Hektoen. Jour. Amer. Med,. Assn. Mav 12, igo6. 

 Simon. Jour. Exper. Med. VIII., No. 6 and IX., No 5. 

 Various articles. Jour. Exper. Med. Vol. IX. 

 Potter, etc. Jour. Amer. Med. Assn. Nov. 30, 1907. 

 Wright. Jour. Amer. Med. As.m. Aug. 10 and 17, 1907. 

 Ross, etc. Jour. Amer. Med. Assn. Oct. 12, 1907. 

 Wright, etc. Lancet. Nov. 2, 1907. 

 Park and Biggs. Jour. Med. Res. Vol. XVII., No. i. 

 ■fJourn. Exper. Med. Vol. IX. pp. 473-4S6. 1907 



