SPUTUM 233 



a proportion of purin bases equal to 0.5 per cent., in similar 

 abscesses after injection of iodoform, 1.57, and in acute sup- 

 puration, 10.7. Spermin crystals are also occasionally found 

 in old pus collections. 1 Free fatty adds and volatile fatty acids, 

 such as butyric, lactic, valerianic, and formic, may also be pres- 

 ent. Products of bacterial activity, such as bacterial proteids 

 and pigments (e.g., pyocyanin), may also be present. (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 2 found 

 evidence of the presence of the following enzymes in pus : 

 proteolytic enzymes, 3 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 acting on amygdalin, sac- 

 charose, 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. 



SPUTUM ^ 



The chemistry of sputum may be properly considered in this 

 connection. In reaction, sputum is ordinarily alkaline, but in 

 case of marked bacterial decomposition in cavities the reaction 

 may become acid. Its specific gravity varies from 1.008 to 

 1.026, usually varying directly with the number of leucocytes ; 

 the average specific gravity is about 1.013. The greenish color 

 frequently observed depends generally upon blood-pigment 

 (except in case of icterus), although in some instances the pig- 

 ment is of bacterial origin. Renk 5 has studied the proteids of 

 sputum with special reference to the loss of proteid to the body 

 and its relation to cachexia. In three patients (consumptives) 

 studied, the daily amount of sputum of two averaged 145 

 grams for each ; for the third it was 82 grams. This contained 

 (average) 5 to 6 per cent, of solids ; including mucin, 2-3 per 

 cent. ; proteid, 0.1-0.5 per cent. ; fat, 0.3-0.5 per cent. ; ash, 

 0.8-0.9 per cent. The daily loss of nitrogen was 0.75 gram, 



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



2 Compt. Rend. Soc. BioL, 1899 (51), 568. 



3 Concerning proteolytic enzymes of pus see Opie, Jour. Exper. Med., 1906 

 (8), 410. 



* Complete bibliography given by Ott, " Chem. Pathol. der Tuberc.," Berlin, 

 1903. 



5 Zeit.f. BioL, 1875 (11), 102. 



