88 THE SECRETIONS : 



pus which previously exhibited no traces of them. The fatty 

 matter of pus contains cholesterin, and, according to the obser- 

 vations of Giiterbock, develops ammonia while burning ; hence 

 the presence of a nitrogenous fat may be assumed. The liquor 

 puris is usually rendered turbid by acetic acid ; the effect may 

 vary from an almost imperceptible cloudiness to a decided 

 precipitate ; if the pus has an acid reaction, this test produces 

 no change. There can be no doubt that the substances which 

 are precipitated in this manner from the liquid parts of pus and 

 mucus are analogous, and that the deposit which occurs in the 

 liquor puris, after the addition of acetic acid, is either actual 

 mucin held in solution by an alkali, or a substance scarcely dif- 

 fering from it, pyin. 1 



The fluid portion of pus, like that of mucus, contains extrac- 

 tive matters and salts ; the former occur in larger quantity in 

 pus than in normal mucus. According to Giiterbock, 2 the salts 

 consist of chlorides, carbonates (arising from the decomposition 

 of lactates), sulphates, and phosphates ; the two latter doubtless 

 arise in part from the oxidation of phosphorus and sulphur 

 during the incineration of the albumen. The bases are potash, 

 soda, lime, magnesia, and traces of iron. According to Martius, 3 

 the pus-corpuscles contain a little phosphate of lime and silica; 

 others have placed the ammonia- salts amongst the constituents 

 of normal pus. 



The liquor puris is strongly precipitated by the mineral acids, 

 metallic salts, and tannic acid, in consequence of its containing 

 albumen, rnucin, and extractive matter : after the addition of 

 a little dilute hydrochloric or acetic acid, it is also precipitated 

 by ferrocyanide of potassium. Small quantities of tubercle 

 occur in the purulent sputa of phthisical patients, in the form 

 of little, white, yellow, or brownish-yellow, irregular, and mo- 

 derately soft masses, varying in dimensions from the size of a 

 grain of sand to that of a small hemp-seed ; they are usually 

 inclosed in mucus, and sink rapidly in water. I have never 

 observed many of these masses in the sputa ; on the contrary, 

 their occurrence was only very rarely noticed, considering the 

 great number of phthisical patients in the Berlin hospital. The 



1 See note, page 74. 2 De pure et granu i at ione, p. 18. 



3 Annalcn der Pharmacie, vol. 24. 



