Inflamation. Plogysis. Phlegmasia. 47 



the blood is deficient in red globules ; (b; in plethora in which 

 there is an excess of blood solids ; (c) in pregnancy in which 

 there is an excess of white and small red globules ; (d) in violent 

 exertion or over-excitement, in which the blood has circulated 

 with extraordinary rapidity. The all-sufficiency of the tissue 

 cells in determining inflammation may be deduced from the fol- 

 lowing experiment. A ligature is tied around a frog's thigh so 

 tightly as to arrest circulation, and the leg amputated above the 

 ligature ; mustard is then applied to the web of the foot and a 

 blister ri.ses precisely as though circulation continued. 



MICROBES, DIAPEDESIS AND PHAGOCYTOSIS. 



The role of microbes in inflammation is much greater than 

 was formerly supposed. It is now demonstrated that a large class 

 of inflammations are directly caused by the colonization of mi- 

 crobes in the tissue and by the local irritation caused by their 

 ptomaines and toxins. We must also admit the direct action of the 

 latter on the heat producing and vaso-motor nervous centres, as 

 a factor more or less potent in different cases in the causation and 

 maintenance of inflammation. No less important is the relation 

 of the microbe to the migration of the globules and the subsequent 

 results of the inflammation. This influence microbes share with 

 certain chemical agents. Migration maj^ be greatly checked even 

 in inflamed parts by the hypodermic or intravenous injection of 

 sulphate of quinia, eucalyptol, salicylic acid, or iodoform. Some 

 have thought these acted by a chemiotactic attraction, but quinia 

 is otherwise found to repel the leucocytes. Their action on the 

 leucocytes or capillary walls is problematic. 



Chemiotaxis is that power by which a microbe or any element 

 attracts or repels the leucocytes. When it attracts the chemio- 

 taxis is said to be positive, when it repels it is negative. Among 

 negative chemiotactic agents are quinia, solutions of sodium chlo- 

 ride (109^), and potassium salts, lactic acid, alcohol (lo^c), chlo- 

 roform, glycerine, jequirity, and bile. To some agents, (creatine, 

 creatinine, allantoin, peptone, phlorydzine,) leucocytes are indif- 

 ferent. To gluten, wheat casein, pea legumin and the great 

 majority of pathogenic microbes, leucocytes are positively attract- 

 ed. As microbes exercise a great influence in producing local in- 



