1 54* Intelligence and Miscellaneous Articles. 



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SEPARATION OF MAGNESIA FROM LIME AND ALUMINA. 

 According to M. Anthon, when tungstate of soda is added to a 

 solution containing the above-nientioned earths, the lime and alumina 

 are precipitated together in the state of tungstates, even should the 

 solution be rather acid : the magnesia is left in solution, and tartaric 

 acid prevents the precipitation of the alumina. Tungstic acid can- 

 not be substituted for the tungstate of soda. 



Journal de Chem. Med, June 1839. 



UREA: MODE IN WHICH IT EXISTS IN URINE. 



According to MM. Cap and Henry, Urea does not exist in 

 urine uncombined, but united with different acids in different beings 

 — in man combined principally with lactic acid ; in ruminating 

 animals with hippuric acid ; in serpents and birds with lithic acid, 

 or at least with the peculiar acid which according to M. Liebig is 

 its radical. 



The natural lactate of urea obtained from the urine of man is 

 identical with the same salt artificially prepared ; the salts of urea 

 are easily obtained by double decomposition. 



Journal de Pharm. Mars 1839. 



LACTATE OF UREA. 



According to MM. Cap and Henry, when urine is evaporated, 

 there is deposited a considerable quantity of crystalline salts, formed 

 principally of chlorides, alkaline sulphates, calcareous and ara- 

 moniaco-magnesian phosphates. If this saline mass be separated by 

 filtration, a brown very acid liquor is obtained, on the addition of 

 alcohol to which, crystalline and hygrometric grains are formed, 

 which when purified by charcoal become prismatic deliquescent 

 crystals, of a sharp taste and which redden litmus paper. If these 

 crystals are treated with hydrate of zinc and with alcohol, there is 

 obtained a lactate of zinc, which is insoluble in the alcoholic liquid, 

 but soluble in water ; and also by evaporation of the alcohol very 

 pure urea, which is not hygrometric, and possessed of all the 

 characteristic properties of that substance. It is then evident that 

 the crystalline grains obtained by the simple concentration of the 

 urine freed from the chlorides and other salts, are principally con- 

 stituted of lactate of urea. 



Artificial lactate of urea is obtained by first preparing lactate of 

 lime by adding slacked lime or chalk to sour milk ; this salt is then 

 decomposed by dissolving 100 parts of it which have been dried at 

 248°, in 200 parts of hot water and 41 parts of crystals of oxalic 

 acid ; this solution contains 75 parts of lactic acid as contained in 

 salts, and there are to be added to it 73 parts of pure dry urea ; the 

 solution is to be filtei'ed, evaporated with a gentle heat, and set to 

 crystallize. 



It is however preferable to prepare lactate of urea by double 

 decomposition, either by treating the oxalate of urea with lactate of 



