ORGANIC ANALYSIS. 



807 



matters. The analysis must afterwards be pro- 

 ceeded with upon the principles already laid 

 down, being first directed to the soluble ingre- 

 dients and then to the insoluble matters. 



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. 



(<i) 3200 grs. we re 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 evaporation, 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 evaporated 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 

 secretion. 



(f) 1000 grs. of urine were evaporated to 

 dryness and exhausted with alcohol. This 

 alcoholic solution was evaporated, the dry mass 

 treated with water, and nitric acid added, 

 with the precautions already mentioned, fur- 

 nished 29.17 grs. of nitrate of urea. 



100 : 29.17 : : 48.78 : x (= 14.23) urea. 



(g) The residue after exhaustion with alco- 

 hol weighed 6.6 grs. It was ignited, and left 

 a saline mass, amounting to 4.46 grs. 



6.6 4.46 = 2.14 organic matter. 

 From this we deduct the uric acid 0.37 (d), and 

 mucus 0.165 (a), the residue 1.605, is " watery 

 extract." 



(//) The portion soluble in alcohol amounts 

 to 43.2 6.6, or 36.6 grs., which we find com- 

 posed as follows : 



The total saline matter of the urine (in- 

 cluding the sulphuric acid volatilized by igni- 

 tion (r) ) 



fixed salts 



8.928 



urea 14.230 



mur. ammonia 0.915 



by (./) 



24.073 

 36.6 24.073= 12.527 alcoholic extract. 



The composition of the urinary salts has now 

 to be determined. 



(') 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. 



(/) 1000 grs. of urine were supersaturated 

 with ammonia ; a bulky precipitate of the 

 earthy phosphates fell, which after ignition 

 weighed 0.65 grs. 



(m) The filtered liquid supersaturated with 

 lime-water gave a precipitate, which weighed 

 after ignition 3.57 grs. 



100 : 3.57 : : 49.1 : .r (= 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. 



(M) 41.5 grs. of the saline residuum left 

 2.45 grs. insoluble in water. 



41.5 2.45 = 39.05 alkaline salts. 



41.5 : 11.8 (c) : : 2.45 : 0.6956 insoluble 

 salts in 1000 urine; by (I) we found the 

 earthy phosphates 0.65. 



H.8 0.7 =11.1 alkaline salts per 1000 

 urine. 



(o) The insoluble portion dissolved in a little 

 nitric acid, supersaturated with ammonia and 

 redissolved in acetic acid, gave by oxalate of 

 ammonia a precipitate which yielded on igni- 

 tion 1.32 grs. carbonate of lime. 



2.45 : 0.6956 : : 1.32 : x (= 0.3753) carb. 

 lime. 



100 : 0.3753 : : 56 : .r (= 0.2101) lime. 



(p) The solution filtered from the oxalate of 

 lime and supersaturated by ammonia gave, on 

 agitation followed by repose for some hours, 

 a crystalline precipitate, weighing 1.18 grs. 

 after ignition. 



