248 QUANTITATIVE ANALYSIS OF PUS. [BOOK I. CH. VI. 



the combined CO 2 which is given off on the addition of an acid; 

 indeed pure pus contains only free CO./. 



4. Pus corpuscles, as doubtless also the colourless cells of 

 the blood, possess the property of decomposing sodium carbonate 

 (Na 2 C0 3 ) and evolving from it CO a . 



5. Pus corpuscles and the colourless cells of the blood are either 

 altogether free from oxygen or contain mere traces of this gas. 



SEC. (j. DIRECTIONS FOR THE QUANTITATIVE ANALYSIS OF Pus. 



1. Determine the specific gravity by means of the bottle (see 

 p. 174). 



2. Ascertain the reaction. 



3. Determine the total solids, water and salts, as in the case of 

 blood (see p. 177). 



4. Evaporate a known weight of the fluid, say 25 grin., to dryness. 

 Extract with ether and determine the amount of the ether extract. 

 If wished, determine in the latter the amount of cholesterin, lecithin 

 and fats, as in the case of blood (see p. 187). 



5. Treat the residue after extraction with ether, with boiling 

 absolute alcohol, filter, evaporate the solution to dryness; weigh, 

 then ignite and weigh again. By subtracting the second from the 

 first weight the amount of the alcoholic extractive matters is found. 



6. Mix a weighed quantity of pus with ten times its volume of 

 alcohol, set aside for 24 hours and proceed exactly as in Schmidt's 

 method for determining the total amount of proteids in the serum 

 (p. 188). In this way will be found the combined weight of the 

 proteids of the pus serum and of the corpuscles, together with 

 nnclein. The residue may then be boiled in water, and, after cooling, 

 subjected to artificial peptic digestion in the incubator for 24 hours. 

 The insoluble matters may be treated with a fresh portion of artificial 



fastric juice and the process continued for a second period of 24 

 ours. The insoluble residue is then collected on a weighed filter, 

 washed successively with boiling water, alcohol, and ether, and then 

 dried; thus will be found the weight of the dry nuclei (nuclein?). 



7. A portion of the pus may be filtered and the solids, salts, 

 extractives, &c. of the pus serum be determined, by following precisely 

 the methods recommended in the case of blood serum. 



8. If it be required to determine the presence of urea, sugar, or 

 any other extractive matter, the methods recommended in the case of 

 blood may be followed. 



9. For the separation and estimation of the gases of pus the same 

 proceedings are adopted as with blood. 



1 The liquid contained in the pleural cavity, if not purulent and of old standing, 

 always yields a larger proportion of firmly combined than of loosely combined or 

 free C0 2 . 



