1867.] 



Esctr active Matters of Urine. — Part II. 



129 



The solution yielded on evaporation a yellov.^, brittle, transparent, gum-like 

 substance, which, when burnt, left a considerable quantity of reddish- 

 yellow ash. Hence it appears that the precipitate with basic acetate of 

 lead contained, besides oxide of lead, other bases in combination with the 

 organic bodies, a portion of it consisting probably of double compounds of 

 extractive matter with lead, alumina, lime, &c. Similar compounds, with- 

 out doubt, were present in the original precipitate thrown down from urine 

 by basic acetate of lead. By the second precipitation a great portion of 

 the alkaline or earthy bases was removed, the portion which rem.ained 

 forming, by combination with a part of the extractive matter, a compound 

 insoluble in alcohol. 



The substance under examination contained, however, in addition to 

 extractive matter, a body having, like glucose, the property of reducing an 

 alkaline solution of copper, a property which does not belong to either of 

 the extractive matters in a state of purity. On mixing the watery solution 

 with sulphate of copper and an excess of caustic soda, it assumed a bright 

 green colour, and on being boiled deposited an abundance of suboxide of 

 copper. The body producing this reaction cannot be separated from the 

 extractive matter insoluble in ether by the use of solvents, since they 

 behave in the same manner towards ordinary menstrua, nor by crystalliza- 

 tion, as both are, as usually obtained, amorphous. Both substances are 

 also precipitated from the watery solution by basic acetate of lead, and 

 from the alcoholic solution by neutral acetate. If, however, a solution of the 

 two substances in waiter contains also earthy and alkaline bases, the glucose- 

 like body tends to combine with these to the exclusion of the extractive 

 matter, and on now evaporating and treating the residue with alcohol, 

 provided a sufficient quantity of bases is present, the alcohol takes up only 

 extractive matter ; but if they are deficient, the solution in alcohol will 

 contain both. On the other hand, the compounds of the extractive matter 

 with bases are less soluble in alcohol than those of the glucose ; so that, on 

 adding alcohol to a watery solution containing compounds of both bodies, 

 the precipitate frequently consists of a compound of extractive matter only, 

 without glucose. With a knowledge of these facts, it is easy to explain 

 why in my experiments I obtained sometimes pure extractive matter, some- 

 times glucose only, and occasionally a mixture of both, without any great 

 difference in the physical properties of the products being observed. 

 That the glucose-like body so often accompanying the extractive matters 

 has a composition similar to that of grape-sugar, and other substances of the 

 same class, was proved by the analysis of its lead compound, the results of 

 which were given in the first part of this memoir. 



A specimen of extractive matter, insoluble in alcohol, obtained by eva- 

 porating a portion of the liquid from which the lead compound of Analysis 

 IV. Series F, was precipitated with acetate of lead and alcohol, and which 

 had been kept for several years in my collection of products from urine, 

 gave on examination similar results. It was a dark brown, shining, 



