INFLAMMATION. 



lion ; but in aci'.te iMfiammrtion, tlie rmitations are quick, 

 aiid the pain is, for the moil part, conlidcrablc. 



The f-.velling appears t.) be oecalioiied bv fcveral circum- 

 ftances, yet principally by the incrcafod determination of 

 blood to the vefll-ls of the part, and by an effulion of co- 

 agulating lymph in the interllices of the cellular fubftance. 

 The dilatation of ihv? blood- vefTels, and the interruption of ab- 

 forption, probably have alfo a fiiare in [iroducing thecft'edl. 



The confiderable injciStion of the fniail vefTels with red 

 blood, and their great incn>afe of diameter, affoid fome cx- 

 j)lanation of the manner in which the preteruatur.d rcdnefs 

 arifes. It has been a prevailing fentiment, that the rednefs of 

 common inflammatitrn is partly owing, not merely to a dila- 

 tation, but at the fame time to an actual incrcafe in the num- 

 ber of the blood-veflels of the iiiflamKd part. New vefTels are 

 fuppofed to be generated. This doctrine, kov%ever, is far 

 from relling upon unqueftionable evidence. When co- 

 agulating lymph is extra vafated upon the furface of a 

 wound, an inflamed membrane, &c. it is beyond a doubt 

 often rendered vafcular, or, in other words, becomes fur- 

 nifiied with new velfels. But, in the extravafated lymph of 

 a phlegmonous tumour, we have no evidence to prove that 

 there is any generation of new veflels. If the veffels have 

 the appearance of being m;;re numerous, it is becaufe their 

 diameters are enlarged, and many, which previonfly con- 

 tained only a colourlefs fluid, are now filled with vifibly red 

 blood. Were the extravafated lympk of a phlegmonous 

 fwelling to be rendered organized and vafcular, the tume- 

 faction and rednefs would probably be more permanent, 

 and not admit (at leall fo cafily as ihey often do) of refo- 

 lution. When adhefions form between two inflamed fur- 

 faces, the organized fiibiliance, forming the connet\ion, lives 

 after the fublideiue of the inflammation, and is a permanent 

 effecl. (Did. of Pracl. Surgery.) According to Mr. 

 Burns, the fuppofition eafdy admits of refutation ; for heat, 

 and many other caufes of inflammation, operate fo quickly, 

 that there can be no time for the formation of any new 

 veffels ; and yet the rednefs is as great, and the inflammation 

 as perfett, in a minute, as in an hour, or a day, after the 

 application of the exciting caufe. (DifTert. on Inflammation). 

 Now that we arc noticing the rednefs of inflamed parts, it 

 may be as well to nr.ention the circumllance of red blood 

 itfelf being fometimes extravafated, in confequence of in- 

 flammation. The occurrence generally indicates, that the 

 infla.nmat( ry raifchief has been rapid and violent. The moll 

 llriking inllances, which juft now prefent themfelves to our 

 mind, are, firit, that ftate of an inflamed eye, termed che- 

 mo/is, for an account of which we refer to Oihthai.my ; and, 

 fecondly, the fpots, produced by effufed blood, on the inner 

 coat of the ilomach, when this vifciis has been inflamed, in 

 confequence of poifon. There is ftill another circumllance, 

 which has been mentioned by the celebrated Mr. John 

 Hunter, as conducive to the red appearance of inflamed 

 parts, viz. the blood, after it has become venous, retaining 

 a certain degree of the bright fcarlet colour, which it pof- 

 felfed in the arteries. We cannot offer any opinion concern- 

 ing the truth of the latter fuggeltion ; as coming from Mr. 

 Hunter, it cannot fail to deferve attention. 



The experiments which Mr. Hunter made with the ther- 

 mometer, tend to evince, that the real augmentation of the 

 heat of an inflamed part is inconfideruble, although it feen.s 

 to be very great, when a judgment is derived from the pa- 

 tient's icehngs. If we recoiled, that the fenfibility of the 

 nerves is augmented, we can no longer be furpri/.ed, that 

 they fhoiild convey to the fenforium falfe impreffions. 

 With regurd to the ma»ncr, in which the incrtafcd ttiiipera- 



ture of inflamed parts is produced, this fubjed is explicable 

 on the principles, which apply to the produdion of ani- 

 mal heat in general. We fliall merely obferve, that there is 

 always a greater determination of blood to a part which i; 

 in a Hate of inflammation, than to the fame part when it 

 is not inflamed. The blood flows through it with aug- 

 mented velocity, and we always find, that the heat of the 

 whole body, as well as of any portion of it, is alv.ays in a 

 ratio to the accelerated Hate of the circulation. When a 

 perfon runs, he hurries the current of the entire mafs of 

 blood, and his whole body is thrown into a heated ftate. 

 In fevers, the circulation is quickened, and there is like- 

 wife general heat. But in inflammation unattended with 

 febrile diforder, the blood flows only through the inflamed 

 part with increafed impetuofity, and, of courfe, the aug- 

 mentation of heat is local and circunifcribed. 



Phlegmon, or what may be called common inflammation, 

 has been regarded by many writers as an afl^edion of the 

 cellular membrane. Its frequent occurrence in every fitua- 

 tion, both internal and external, has been accounted for by 

 the way, in which the cellular fubftance pervades the tex- 

 ture of almoll every part of the body. Phlegmon is re- 

 prelented as being attended with more fwelHng than 

 any other fpecies of inflammation. The bright red co- 

 lour in the centre of the tumour gradually extends towards 

 the circumference, and is infeniibly loH on the furrounding 

 fkin. The fwelling, on the other hand, is dillinctly cir- 

 cunifcribed. The heat has been compared with that arifing 

 from the ftcam of boiling water. The throbbing, to which 

 we have already adverted, manifefUy depends upon the pul- 

 fation of the arteries, and is fynchionous with the pulfe of 

 the whole fyltem. The throbbing particularly aflPeds the pa- 

 tient himfelf, and the furgeon may plainly perceive it when 

 he touches the part, all the fmall vefTtls of uhich are di- 

 lated, and beat in a preternatural degree. In a common 

 whitlow, this vehement throbbing is not confined to the 

 finger, but extends to the large arteries, a confiderable way 

 up the arm. 



The adive mind of the late Mr. John Hunter led him to 

 pay much attention to the interefting fubjed before us, and 

 from him we have many fertile and original obfervations. 

 The principles and laws of inflammation were better ex- 

 plained by this philoTophieal obfcrver, than by any of His 

 profeffional predecefl'ors. He has uoticed the well efla- 

 blifhed circumllance, attending phlegmonous and other in- 

 flammations, whcrefoever fituated, namely, their being al- 

 ways moil violent on the fide next to the external furface of 

 the body. Thus, when inflammation invades the focket of 

 a tooth, it chiefly takes place towards the cheek, and not 

 on the infide of the alvcolary procefs. He point.5 out, 

 that the titnation, pofition, flrudure, fundions, and dillance 

 of the part affefted from the fource of the circulation, 

 caufe confiderable variety in the progrefs and termination 

 of all inflammation. He maintains, that parts, naturally 

 enjoyir.g a vigorous circulation of blood then can bear in- 

 flamnuation better than others in the oppofite condition. 

 From this obfcrvation, however, he excepts vital parts, 

 which, though they may be exceedingly valcular, do not 

 undergo inflammation favourably, becaufe the natural ope- 

 rations of univerfal health depend fo much upon.the found- 

 nefs of fuch organs. Mr. Hunter alfo endeavours to fliew, 

 that the depending pofition of a part feems to have a ba(i 

 effcd on inflammation, probably by retarding the return 

 of the blood. It is one of the fame author's principles, 

 that new-formed parts, as many tumours and excrefcenccs, 

 callus, fears, ^:c. poifefs lefs vitality than is the iliare of 

 N 2 other 



