808 



ORGANIC ANALYSIS. 



2.45 : 0.6956 : : 1.18 : x (= 0.3345) 

 100 : 0.3345 : : 35.71 : x (=0.1198) mag- 

 nesia, 

 (q) 0.6956 (0.2101 + 0.1198) = 0.3659 



phosphoric acid with the earths. 

 0.3659 + 1.753 (m) =2.1189 total phos- 

 phoric acid in 1000. 



(r) 15 grs. of the alkaline salts (n) were dis- 

 solved in water and converted into chlorides 

 by admixture with chloride of barium in ex- 

 cess ; a precipitate of 6.4 grs. of sulphate and 

 phosphate of baryta formed ; on treating this 

 precipitate with nitric acid, 0.45 sulphate of 

 baryta remained. 



15 : 11.1 (n) : 0.45 : 0.333. 



100 : 0.333 : : 34.19 : 0.114 sulphuric acid 



in the ash, from 1000 parts of urine. 

 But 1000 grs. of urine we found (by /c) to 

 contain 1.702 grs. sulphuric acid, therefore 

 1.702 0.114 = 1.588 grs. of sulphuric acid 

 have been expelled by ignition. 



(s) The filtered solution was heated with 

 caustic and carbonated ammonia to precipitate 

 the excess of baryta as carbonate. The whole 

 filtered, evaporated to dryness, and ignited to 

 expel the ammoniacal salts. The fixed chlo- 

 rides weighed 14 grs. They were dissolved in 

 water, treated with bichloride of platinum, eva- 

 porated nearly to dryness by a water- bath, 

 then treated with alcohol, the platino-chlonde 

 of potassium amounted to 1 3.40 grs. 

 15 : 11.1 : : 13.40 : 9.916. 

 100 : 9.916 : 19.43 : : x (= 1.926) potash. 

 () But 247, (1 eqt.platino-chlor. potassium) 

 : 13.40 : : 76, (1 eqt. chlor. potassium) 

 : x (= 4.123) chloride potassium, and 

 14 4.123 = 9.877 chloride sodium. 

 15 : 11.1 : : 9.877 : x (= 7.3089) chloride 



sodium, 



and 60, (1 eqt. chlor. sodium) : 7.3089 : : 24 

 (1 eqt. sodium) : x (= 2.9235) sodium. 

 (w) 10 grs. of the alkaline salts were dis- 

 solved in water, the solution acidulated with 

 nitric acid, and nitrate of silver added in slight 

 excess : the precipitate of chloride of silver 

 amounted to 15.61 grs. 



10 : 11.1 : : 15.61 : x (= 17.3271) 

 100 : 17.3271 : : 25 : x (= 4.3317) chlo- 

 rine in the ashes of 1000 parts of urine. 

 We find the equivalent quantity of sodium 

 as follows : 



36 : 4.3317 : : 24 : x (= 2.8878) sodium, 



equivalent to the chlorine. 

 The chloride of' sodium therefore amounts to 

 7.2195 grs.; deducting the sodium com- 

 bined with chlorine from the entire quan- 

 tity in the urine (t), we obtain 

 2.923562.8878 = 0.03576, or 0.0536 



soda. 



(v) Now before ignition the chlorine (by i) 

 amounted to 4.942 grs. 

 deduct. . . . 4.3317 combined with so- 



dium in the ash. 



0.6103 chlorinevolatilized, 

 probably in the form of muriate of am- 

 monia, the amount of which appears by 

 the following calculation : 

 36 : 0.6103 : : 54 : x (= 0.9154) muriate 

 ammonia. 



999.9623 



In analysing diabetic urine the method must 

 be modified, as will be seen by the following 

 example. 



It was feebly acid, and had a specific gravity 

 of 1038. 



Evaporated in vacuo over sulphuric acid, 

 it furnished a pale amber-coloured soft mass, 

 which weighed, 



On the third day .... 55.9 grs. 



sixth 54.1 



ninth 53.4 



fourteenth . . . 53.1 



thirtieth 52.2 



The temperature varied between 60 and 70, 

 and the vacuum shewed from 1 inch to 1^ 

 inches on the pressure gauge. 



The presence of even a very small portion 

 of air materially retards the progress of the 

 evaporation. 



From the weight on the thirtieth day we find 

 500 : 1000 : : 52.2 : .r (= 104.4) solid 

 contents, and 



1000104.4 = 895.6 water. 

 As a contrast to this evaporation in vacuo, 

 the remainder from 500 grs. was evaporated 

 by water-bath, the temperature never rising 

 above 180F. 



In 24 hours the residue weighed 48.4 grs. 



48 46.9 



72 46.1 



96 46.0 



By this time it had assumed a deep brown 

 colour, and from being soft and sectile had, 

 with the exception of a small portion in the 

 centre, become hard and brittle ; by exposure 

 to the air it speedily deliquesced; 30. 6 grs. of 

 the dry mass dissolved in water was mixed 

 with 16.7 grs. of yeast, which from the eva- 

 poration of another portion was found to con- 

 tain 3.5 grs. of solid matter. The mixture 

 was set aside for four days at a temperature of 

 70 to ferment ; gas was slowly disengaged; 

 when fresh bubbles ceased to form, the solu- 

 tion was evaporated to dryness, and amounted 

 to 25.8 grs. ; deducting 3.5 solid matters of 

 the yeast, we have an unfermentable mass of 



* The sulphuric acid has been deducted from the 

 amount of organic matter determined by b and v, 

 and added to that of the saline matters. 



