CHAPTER XI 



INFLAMMATION' 



Although morphological alterations are prominent features of the 

 reaction of the tissues to local injury and infection, yet at the bottom 

 the processes of inflammation are brought about by and result in 

 chemical alterations. The causes of inflammation are in nearly all 

 cases chemically active substances, but for the most part their nature 

 is too little known to permit of speculation as to what chemical char- 

 acteristic or characteristics a substance must possess to exhibit the 

 power of causing an inflammatory reaction. Even in the case of in- 

 flammation due to mechanical, thermal, and electrical injuries, it 

 seems probable that most of the features of the inflammatory reaction 

 are brought about by the action of chemical substances produced by 

 alterations in the tissue constituents at the point of injury,^ for tissue 

 proteins that have been altered in necrosis are chemotactic,^ as also 

 are extracts of tissues. 



The essential features of inflammation, namely, local hyperemia 

 and related vascular disturbances, exudation of plasma, migration of 

 leucocytes and their phagocytic action, all may be caused by the action 

 of chemical substances upon the vessels and leucocytes. Active hy- 

 peremia in the case of inflammation is due to stimulation of the vaso- 

 dilator nerves or paralysis of the vaso-constrictors, or direct par- 

 alysis of the muscular fibers of the arterioles; these may result from 

 mechanical, thermal, or electrical stimuli, but in local infection the 

 cause is usually chemical products of bacterial growth or of tissue 

 disintegration. The escape of blood plasma (inflammatory edema) 

 appears to depend upon a number of factors (discussed more fully 

 under "Edema," Chap, xiv) of which the most important seem to be: 

 (1) injury to the capillary walls, produced largely by the chemical 



1 For extensive reviews and bibliography see Adami, in Allbutt's System of 

 Medicine; reprinted also as a naonograph, "Inflaninuition," 1909; also Opie, Arch. 

 Int. Med., 1910 (5), 541. Some interesting ideas are advanced by Klemensiewicz, 

 "Die Entziindung," G. Fischer, Jena, 1908. 



2 Schlaepfer (Zeit. e.xp. Path., 1910 (8), 181) finds that the reduction of methj-- 

 lene blue is decreased in inflammatory areas, and advances the hypothesis that 

 inflammatory stimulants are o.xidation stimulants, inflammation occurring only 

 when the amount of oxidation aroused by the stimulant is insufficient. In accord 

 with this is the observation of Amberg (Zeit. exp. Med., 1913 (2), 19) that sub- 

 stances facilitating oxidation reduce inflammatory reactions. (See also WooUey, 

 Jour. Amer. Med. A.ssoc., 1914 (63), 2279.) Another observation of similar sig- 

 nificance is that phagocytosis is stimulated by H2O2, and that phagocytes react 

 to HNC in the same wav as the respiratory center (Hamburger, Internat. Zeit 

 phys.-chem. Biol., 1915 (2), 245-264). 



3 Burger and Dold, Zeit. Immunitat., 1914 (21), 378. 



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