C. PROXIMATE ANALYSIS OF INDIVIDUAL SECRETIONS.
1. Of the urine.
The following is a detailed example of the method of analysing healthy urine: As there was abundance of the fluid for exa mination, fresh portions were taken whenever it seemed desirable to do so for determining any particular ingredient.
• The secretion had a sp. gr. of 1020.4. It distinctly reddened litmus paper, and exhi bited a slight cloud of floating mucus.
(a) 3200 grs. were filtered through a weighed filter, and the mucus collected. It amounted to 0.53 grs.
3200 : 1000 : : 0.53 : x (= 0.165) mucus.
(b) 200 grs. evaporated in a counterpoised capsule left 8.64 grs.
200 : 1000 : : 8.64 : x (=-- 43.2) solid mat ters.
1000 - 43.2 = 956.8 water.
(c) The residue, 8.64 after evapomtion, ig nited in the capsule left 2.36 grs. of saline matter.
200 : 1000 : : 2.36 : x (= 11.8)fixed salts.
(d) 1000 grs. of urine (freed from mucus by filtration) was evapomted to dryness in a pla tinum capsule. It was treated with water, acidulated with hydrochloric acid, and left 0.37 grs. of uric acid ; after incineration of the uric acid a trace of silica remained.
(e) During the last three years I have made many careful analyses of the urine with express attempts to obtain from it the lactic acid it is said to contain; but though I employed various methods, and in some instances large quantities of urine, I have never succeeded in eliminating it from fresh urine, and I therefore (as the methods used were capable of detecting small quantities of the lactates when purposely mingled with the urine) concluded that lactic acid is not a normal constituent of human 'urine. Liebig has lately stated the same fact ,founded on his own recent examinations of the ecretion.
(f) 1000 grs. of urine were evaporated to ryness and exhausted with alcohol. This lcoholic solution was evaporated, the dry mass ted with water, and nitric acid added, ith the precautions already mentioned, fur 'shed 29.17 grs. of nitrate of urea.
100 : 29.17 : : 48.78 : (=-- 14.23) urea.
(g) The residue after exhaustion with alco ol weighed 6.6 grs. It was ignited, and left saline mass, amounting to 4.46 grs.
6.6-4.46 = 2.14 organic matter.
'rom this we deduct the uric acid 0.37 (d), and nucus 0.165 (a), the residue 1.605, is " watery tract." (h) The portion soluble in alcohol amounts 43.2-6.6, or 36.6 grs., which we find com ,osed as follows : • The total saline matter of the urine (in luding the sulphuric acid volatilized by igni ou (r) ) amounts to..13.388 grs. (= 11.8 + 1.588) deduct 4.46 salts insoluble in alcohol (g) remain .... 8.928 salts dissolved by alcohol.
fixed salts 8.928 urea 14.230 by (f ) mur. ammonia 0.915 by (v) 24.073 36.6-24.073= 12.527 alcoholic extract.
The composition of the urinary salts has now to be determined.
(i) 1000 grs. of urine were acidulated with nitric acid, and mixed with a solution of ni trate of silver, an abundant precipitate of chloride of silver ensued.
The filter with the precipitate weighed 39.13 The filter alone 15.23 - Total wt. of the chloride before fusion 23.90 - 23.12 of chloride fused in a counterpoised porcelain capsule gave 19.12 grs., weight of chloride after fusion.
23.12 : 23.90 : : 19.12 : x (= 19.77) fused chloride silver.
100 : 19.77 : : 25 : x (= 4.942) chlorine.
(k) The filtered liquid was treated with nitrate of baryta, the precipitate collected, well washed with boiling water, ignited, weighed 4.97 grs.
100 : 4.97 : 34.19 : x (= 1.702) sulphuric acid.
(l) 1000 grs. of urine were supersaturated with ammonia ; a bulky precipitate of the earthy phosphates fell, which after ignition weighed 0.65 grs.
(rn) The filtered liquid supersaturated with lime-water gave a precipitate, which weighed after ignition 3.57 grs. • 100 : 3.57 : : 49.1 : x 1.753) phosphoric acid, which is in combination with al kaline bases.
To determine the bases a considerable por tion of urine was evaporated, and the residue burned to whiteness.
(n) 41.5 grs. of the saline residuum left 2.45 grs. insoluble in water.