3g: OBSERVATIONS AND EXPERIMENTS ON PUS. 



tion occurred on dilution with water, and on saturation with 

 the fixed alkalis, but a trifling sediment appeared, which 

 redissolved on the addition of the above acids, 

 mineral acids 2. The mineral acids diluted, or added in small propor- 

 **''"f®^» ^'^'^ tion, and the vegetable acids, coagulate variously pus and 

 acsds, mucous fluids. Some become merely milky fluids, others 



curdy tluids, otheis afford fibrous and leaf} masses in atrans- 

 parent liquor, and others give a uniform thick mass of curd. 

 On standing the deposits are accordingly of various forms, 

 and the liquors above of various appearances; but I could 

 discover no constant characteristic property of the sub- 

 stances by these experiments, as some writers have asserted. 

 iixecl aTfcalis 3. The solid fixed alkalis, or lime, mixed with expecto- 



and hiEe, rated mucus, occasion a stronger smell of ammonia than 

 with pus; or than with rauco-purulent sputum. Some use 

 may be perhaps made of this easy experiment to judge of 

 the nature of varieties of the fluids in question, particularly 

 as far as depends on the proportion of ammonia; for some- 

 times it cannot be perceived by the smell on mixing alkalis, 

 ftronp solu- but can by muriatic acid giving white vapobrs. Concen- 

 ttonsofaikahs, fj-ated liquid alkalis, added to both pus and mucus, dissolve 

 thera to produce clear liquifl?, except small curdy parts and 

 motes. These curdy parts and motes resist dissolution also 

 for some time even in nitric acid, and seem to be self-coagu- 

 laited lynnph. They are in much greater proportion in pus 

 than mucus. The addition of acids to these alkaline disso- 

 lutions occasions precipitations : but no differences, or not 

 with sufficient uniformity to afford criteria, were observed 

 according to the observations of other experimenters, 

 atronrsolu- 4. Concentrated aqueous^ solutions of various neutral 



tjoTisofneu- salts, viz. muriate of ammonia; nitrate of potash; muriate 

 ltd aaus, ^^ soda; sulphate of soda, &c. ; being mixed in due quan- 



tity with pus of the kinds under examination, produce vis- 

 cidity, like ropy expectorated matter, thickening like jelly, 

 and less opacity. These changes have, in the case of muri- 

 ate of ammonia, been called coagulation by Mr. Hunter; 

 but by agitation in cold water the matters are diff'used, and 

 on standing, the pus is precipitated in its original state. I' 

 call these effects of the neutral salts inspissation, seemingly 

 •ccasjoned by their attracting water from the pus; for no 



such 



