INFLAMMATION. 15 



ducing material and leucocytes, and is consequently liable to coagulate in the 

 tissue's if allowed to remain in them. The result of this coagulation will be 

 the formation of fibrous bands (adhesions), which will, more or less, interfere 

 A\ith the movement of the part. The swelling will also lower the vitality and 

 strength of the part by impeding its circulajtion. The most rational means 

 for the removal of the^xudation, is massage (p. 664) and external pressure 

 (for an example see page 45), which may be increased considerably 

 bevond that which had existed in health. During the course of unchecked in- 

 flammation, the blood pressure on the walls of the capillaries causes these 

 vessels to increase greatly in size. In fact, granulations (the small, rounded 

 excrescences of " proud fl'esh") in a wound, consist, as explained by Hamilton, 

 of bunches of abnormally distended capillary loops. 



(Edema (the accumulation of fluid beneath the skin) may al^o result from 

 passive congestion, especially when the part has been weakened by previous 

 attacks of inflammation, as in the case of the filled legs of hor.es which have 

 done a good deal of work. 



Inflammation is generally characterised by pain, heat, swelling, and, if the 

 skin be thin and white, redness. The pain is due to pressure on the nerves of 

 the part ; and the swelling, as we have already seen, to the exudation of lymph. 

 The redness, and the heat, which, according to John Hunter, is never in 

 excess of that in the interior of the body, are caused by the presence of an 

 increased supply of blood, as in blushing, for instance. 



REPAIR AFTER INFLAMMATION.— The leucocytes which escape from 

 the capillaries into the tissues during inflammation, appear to be of two 

 kinds, namely, one which supplies fibrin-ferment to the exuded plasma ; the 

 other which devours dead matter and invading disease germs. These 

 scavengers, having absorbed into their substance w^aste and hurtful material, 

 may, if few in number, be carried away by the lymphatics. If they are too 

 numerous — by reason of the intensity of the inflammation — for this to happen, 

 the cells of the part, after the inflammation has begun to abate, may, in their 

 turn, abiorb the leucocytes which are present and any remaining debris or 

 germs, and may then proceed to repair the injury by scar-tissue, as in wounds 

 (p. 63). During the acute stage of inflammation, the cells of the injured 

 part seem to remain paralysed, and do not perform their scavengering and 

 microbe-devouring function until reaction sets in. The leucocytes, on the 

 contrary, play that role from the beginning of the inflammatory process. The 

 method of repair which I have just described, generally takes place in severe 

 cases of sprained tendon and ligament, in which the presence of the scar-tis^^ue 

 and of the coagulated exudation will be manifested by thickening of the part. 

 If the migrated leucocytes be in too great numbers to be thus removed, they 

 will in all probability die. " When inflammation is followed by an accumula- 

 tion of leucocytes and of pla^^ma which does not coagulate, the result is a 

 white or creamy liquid called pus, and when the surrounding tissues are 

 involved, so that a cavity develops containing pus, w^e have what is termed 

 an abscess "' [CrooJcshanh). The plasma (serum) of pus does not cogulate, 

 because it is devoid of fibrinogen. A.though pus may be an innocuous fluid 

 when it is produced by leucocytes, it is usuaKy of bacterial origin, in which 

 case it contains bacteria that excrete a substance which causes the pus to 

 have a corrosive action on the tissues ; hence, the necessity for the destruction 

 of these bacteria and the removal of the pus. Kanthack tells us that an xdcer 

 may be compared to an open abscess, and that the granulations formed in both 

 cases, are the result of an attempt to repair, made by the attacked tissues. 



Although pus miscrohes arc* almost invariably to be found m the collection of 

 pus formed under natural conditions ; it is possible for pus to ba produced in 

 the tissues by the introduction of chemical irritants (croton oil, for instance), 

 without the presence of pus microbes. This microbe-free pus being composed 

 of dead and inert matter, has no power to increase in amount. Pus organisms 

 are found abundantly in impure air, polluted water, on skin and on m.ucous 

 membranes, even when these two surfaces are in the highest possible state of 



