PUS. 159 



case of the blood and the transudations, to show the presence of 

 alkaline carbonates and/ree carbonic acid in the pus. 



In the pus, as in almost all other exudations, we meet with 

 bile-pigment, the biliary acids, urea, and sugar, as incidental 

 constituents. 



Glycocholate and taurocholate of soda were found by one of 

 my pupils in pus from a large abscess in the thigh of a patient 

 with catarrhal icterus ; another pupil found sugar in the purulent 

 discharge yielded by the blistered surface of a patient with 

 diabetes. 



We may conclude with the supplementary remark, that mor- 

 phological elements which do not, strictly speaking, pertain to pus, 

 are sometimes found in it ; amongst these we must reckon the 

 fibrin ous coagula which are often met with in suppurative exuda- 

 tions when they liquify into pus (pneumonic sputa). In the pus 

 of old abscesses, and in the ichorous discharge from ulcers, we 

 very often find crystals of phosphate of magnesia and ammonia, 

 not unfrequently vibriones, and sometimes microscopical fungi and 

 confervse. 



Acid pus is probably of very rare occurrence in the animal 

 body ; when pus has continued stagnant for a considerable time in 

 the cavity of an abscess (in what are termed cold or congestive 

 abscesses), it very generally undergoes alkaline fermentation ; it then 

 contains some carbonate of ammonia and triple phosphate, besides 

 a large amount of sulphide of ammonium. I have only found the 

 purulent exudations present in some few cases in empyema. 

 Phthisical patients sometimes expectorate sputa having an acid 

 reaction, although no acid substance had come in contact with the 

 expectorated matters, either whilst they were passing through the 

 mouth or after they were thrown up. The rare occurrence of acid 

 pus is the more remarkable, as it very rapidly turns sour on being 

 left in imperfectly closed vessels. When healthy pus is suffered 

 to remain for several days in a corked bottle containing a certain 

 amount of air, and exposed to a summer temperature, we find on 

 examining it under the microscope, that the corpuscles have 

 swelled and become more transparent, whilst the fissured nuclei 

 are also speedily brought more distinctly into view ; after a longer 

 time the reaction is decidedly acid ; numerous isolated nuclei 

 without a trace of cell-walls, and some few perfect corpuscles, are 

 seen under the microscope, and interspersed amongst the cor- 

 puscles and the nuclei are innumerable molecular granules, whilst 

 here and there we may detect tablets of cholesterin and a confused 



