PUS. 



or natural fluid ; and hence it was concluded, that when- 

 ever n;lobules were found fwimming in a fluid, coagu- 

 lable by fal ammoniac, the matter was to be confidL-red 

 as pus. 



The proportion which the white globules bear to the 

 other pai'ts of pus, depends on the health of the parts pro- 

 ducnigthe difcharge. When the globules are very abun- 

 dant, the matter is thicker and whiter, and is called healthy 

 pus ; the meaning of which is, that the folids, which pro- 

 duced it, are in good health ; for thefe appearances in the 

 matter are no more than the refult of certain falutary 

 proCefles going on in the folids, the effeft of which pro- 

 cefles is to produce the difpofition, on which both fuppura- 

 tion and granulation depend. 



Pus is fpecifically heavier than water, and is probably 

 about as heavy as blood. 



Befides the above properties, pus has a fweetilh mawkifh 

 taite, very different from that of moll other fecretions, and 

 the fame tafte takes place, whether it is pus from a fore, or 

 an irj-itated inflamed furface. 



Pus has a fmell in fome degree peculiar to itfelf ; but 

 this differs in different cafes. Some difeafes, it is faid, 

 may be known by the fmell, as, for inftance, a gonon-hoea. 



Pus finks in water ; mucus floats. Pus communicates 

 to water an uniformly troubled white colour ; mucus gives 

 the appearance of Itringy portions floating in it. Mucus 

 is faid to be more readily diflolvcd by fulphuric acid than 

 pus IS. It has alfo been aflerted, that if water be added to 

 iuch folutions, the pus is precipitated to the bottom of the 

 veflel ; while the mucus, inilead of being completely pre- 

 cipitated, forms fwimming flakes. A folution of cauftic 

 alkali diflolvcs both pus and mucus ; but when water is 

 added, the pus is faid to become feparated, but not the 

 mucus. 



Though folutions in chemical menftrua and precipitations 

 have been thought a teft of the diftmftion between thefe 

 'two fluids ; yet the method has been thought abfurd and 

 unphilofophical. It has been conceived, that all animal 

 fiibftances whatever, when in folution, either in acids or 

 alkalies, vvould be in the fame ftate, and therefore, that the 

 precipitation would be the fame in all. Calcareous earth, 

 when diffolved in muriatic acid, is in that acid in the fame 

 ftate, whether it has been difiblred from chalk, limeftone, mar- 

 ble, or calcareous Ipar, and precipitations from all are the 

 fame. Hence experiments were made on organic animal mat- 

 ter, fuch as mufcle, tendon, cartilage, liver, and brain ; and on 

 inorganic, fuch as pus and the white of an egg. All thefe 

 fubrtances were didolved in lulphuric acid, and precipitated 

 with the vegetable alkali. Each precipitation was examined 

 with fuch magnifiers as plainly fliewed tlie forms of the 

 precipitates, all which appeared to be flaky fubftances. 

 The precipitate by the volatile alkah had exaftly the fame 

 appearance. The fame' appearances were feen when the 

 above kinds of animal matter were diffolved in the vegetable 

 cauftic alkali, and precipitated with the muriatic acid. A 

 flaky fubftance, void of any regular form, compofed each 

 precipitate. 



Pus does not irritate the particular furface which fecretes 

 it, though it may be irritating to any other. Hence no 

 fuppuratmg furface, of any fpecific kind, can be kept up 

 by its own matter. If this had not been the cafe, no fore 

 of a fpecific quality, or producing matter of an irritating 

 kind, could ever have b:-en healed. This is fimilar to every 

 other fecrftion of ftimulating fluids, as the bile, tears, Sec. 

 which fluids do not ttimulate their own glands or dufts, 

 but are capable of ftimulating any other part of the body. 



Whenever a real difcafe attacks either the fappurating 

 furface or the conftitution, the produftion of true pus 

 ceafes, and the fluid becomes changed in fome meafure, in 

 proportion to thefe morbid alterations. In general it be- 

 comes thinner and more tranfparent, and it partakes more 

 of the nature of the blood, as is the cafe in moft other 

 fecretions under fimilar circumftances. Sanies is the term 

 ufually applied by furgeons to pus in this degenerated ftate. 

 This unhealthy fort of matter has more of the ferum, and 

 frequently more of the coagulating lymph in it, and lefs of 

 the combination, which renders it coagulable by a folution 

 of fal ammoniac. It has alfo a greater proportion of the 

 extrane(<u3 parfs of the blood, which are folubie in water, 

 fuch as falts ; and it has a greater tendency than true pus 

 to become putrid. Such unhealthy matter may even be 

 irritating to the furface which produces it. 



The difcharge, when of an irritating fort, is more ftimu- 

 lating to the adjoining parts with which it comes in contaft, 

 than to its own fecreting furface. In this manner it fre- 

 quently produces excoriation of the fliin and ulceration. 

 Thus the tears excoriate the i\<m of the cheek, in confe- 

 qucnce of the quantity of falts which they contain. From 

 this effeft, matter has been called corrofive, a quality which 

 it has not ; the only property which it pofleftes being that 

 of irritating the parts which it touches, fo as to caufe their 

 abiorption. 



When the veffels thus lofe tlie power of producing good 

 pus, they alfo lofe more or lefs the power of forming 

 granulations. This may depend on fome deviation from 

 the due ftrufture and aftion which fuch veflels ftiould 

 poffefs, in order to be qualified for the performance of thefe 

 two operations. 



PLs, from feveral circumftances, would appear in general 

 to have a greater tendency to putrefaction than the natural 

 juices have ; but, perhaps, this is not the cafe with pure 

 pus, which, when firft difcharged from an abfcefs, is com- 

 monly perfeftly fweet. There are, however, fome excep- 

 tions to this, but thefe depend on circumftances entirely 

 foreign to the nature of pus itfelf. Thus, if the abfcefs had 

 any communication with the air, while the matter was cen- 

 fined in it ; or if the colleftion has been fo near the colon, 

 or rectum, as to have been infefted by the feces, then we 

 cannot wonder that the matter ftiould become putrid. 

 W^hen blood is blended with pus ; when floughs are mixed 

 with it ; when the parts forming the feat of the abfcefs are 

 in a gangrenous ftate from an eryfipetalous affeftion ; the 

 matter has a greater tendency to putrify than the pure pus 

 difcharged from found abfcelfes, or healing fores. Pure 

 matter, though eafily rendered fufceptible of change by 

 extraneous additions, is in its own nature tolerably uniform 

 and immutable. It appears fo unchangeable, that we find 

 it retained in an abfcefs for weeks, without having under- 

 gone any alteration. Thefe qualities, however, only belong to 

 perfeft pus. 



In the preceding paragraph it is ftated, that matter remains 

 very often unchanged in abfceffes for weeks. This expreffion 

 of Hunter's is not ftriftly correft ; for it is well known, that 

 the furfaces of the cavities of abfceffes are always abforbing, 

 as well as fecreting ones ; confequently there muft be a conti- 

 nual mutation going on in the contained matter. 



When there are difeafed bones, or other extraneous 

 bodies, exciting irritation, fometimes even to fo great a 

 degree as to make the veffels bleed, and often wounding the 

 veffels of the part, the matter is always found to be very 

 offenfive. This ftate of the difcharge is one mark of a 

 difeafed bone. 



The 



