272 INFLAMMATION 



ino- or polyamino-acids in a liter of pus, which may depend on their 

 having been either absorbed or transformed into ammonium com- 

 pounds. Presumably this is in part the explanation of the large 

 urea excretion in persons with extensive suppuration, as observed by 

 Ameuille.- From the nucleoproteins 'purine bodies are formed and 

 may be found in the pus. The relation of the purine bases to local 

 leucocytosis is shown by Heile,^^ who found in cold tuberculous ab- 

 scesses a proportion of purine bases equal to 0.5 per cent., in similar ab- 

 scesses after injection of iodoform, 1.57, and in acute suppuration, 

 10.7. Spermin crystals are also occasionally found in old pus col- 

 lections.^ Free fatty acids and volatile fatty acids, such as butyric, 

 lactic,^ valerianic, and formic, have been found. Products of bac- 

 terial activity, such as bacterial proteins and pigments (e. g., pyo- 

 cyanin), may also be present. It is probable that in many instances 

 these autolytic products are bactericidal, and thus help to terminate 

 the infection. Direct tests have shown that the autolysate of fibrin is 

 bactericidal for staphylococci and streptococci.^ See also discussion 

 of "Autolysis of Exudates" (Chap. iii). 



All the numerous enzymes of the blood plasma, the leucocytes and 

 the tissue-cells, are present in pus. Thus Achalme® found evidence 

 of the presence of the following enzymes in pus: proteolytic en- 

 zymes,^ lipase (splitting monobutyrin), diastase, rennin (coagulating 

 milk), gelatinase, catalase, and oxidase, the last being very abundant. 

 These seem to exist chiefly in the leucocytes, the pus serum being 

 quite free from them. No evidence could be found of enzymes act- 

 ing on amygdalin, saccharose, inulin, or lactose. Fibrin ferment is 

 said to be absent from pus, which is quite surprising in view of the 

 fact that this enzyme is generally considered as being derived chiefly 

 from the leucocytes. Presumably the bacteriolytic "endolysins" of 

 the leucocytes are also present in pus. 



There is little difference in the effect on metabolism produced by a 

 sterile suppuration and one due to localized bacterial infection (Cooke 

 and Whipple),^ one of the chemical features in each being a precipitous 

 and sustained rise in the urinary N excretion. Presumably the reac- 

 tion in both cases results from toxic products of protein cleavage, 

 rather than from bacterial secretions in the case of septic inflanmiation. 

 Probably only part of the excessive urinary N comes from the local 

 injury, the greater part being derived from toxicogenic destruction of 

 tissue proteins. 



i^Bull. Acad. M(:^d. Paris, 1917, (78), 8. 



3 See Williams, Boston Med. and Surg. Jour., 1901 (145), 355. 



'' d-lactic acid i.s a constant constituont of i)us from the pleura (Ito, Jour. 

 Biol. Chom., 1910 (2(5) 173). 



" Bilancioni, Arch, (li Farmacol., 1911 (11), 491. 



8 Compt. Rend. Soc. Biol., 1899 (51), 568. 



^ Concerning proteolytic enzymes of pus see Opie, Jour. Exper. Med., 1906 (8), 

 410. 



8 Jour. Exp. Med., 1918, (28), 222. 



