312 Intelligence a?id Miscellaneous Articles. 



PREPARATION OF UREA, BY M. HENRY, JUN. 



Add a slight excess of subacetate or hydrate of lead to fresh iiruie ; 

 the precipitate contains the salts formed by the union of the me- 

 tallic oxide with the acids of the saUs of the urine, and a compound 

 produced by the combination of the mucus and a great part of the 

 animal matter, with the hydrate or subsalt employed *. 



The decanted fluid is treated with diluted sulphuric acid slightly in 

 excess, to separate all the lead, and to act afterwards during evapo- 

 ration upon the acetates of soda and lime which may be formed. 

 After having separated the white precipitate, the liquid is quickly 

 evaporated, and animal charcoal added during ebullition. When the 

 fluid is clear, it is to be strained through a fine cloth, and evaporated 

 to about one third of its bulk ; on cooling, the liquor frequently be- 

 comes a yellowish acicular crystalline mass, consisting of much urea 

 and some salts. The crystals when drained and pressed are to be 

 added to those produced by evaporating the mother water, also simi- 

 larly treated ; being thus deprived of the brown viscous matter which 

 enveloped them, the crystals are to be treated with a small quantity 

 of carbonate of soda, to decompose any acetate of lime which may 

 remain, and they are then to be digested in alcohol ; tiio solution 

 filtered and distilled leaves urea, which may be re-crystallizcd by so- 

 lution in water and evaporation. — Journal de Pharmacie, April, 1829. 



A NEW PYROMETER, BY M. POUILLET. 

 This instrument is an oval vessel of platina, soldered to a tube of 

 the same metal of known capacity : this vessel communicates with a 

 graduated tube, so that the increase of volume occasioned by the rise 

 of temperature may be immediately read. To use this pyrometer, 

 tiie platina vessel is to be placed in the furnace, the temperature of 

 which is to be known ; the original volume of the air or gtis contained 

 in the instrument being known, the temperature is determined by the 

 inqrease of its volume. — Ibid. 



POISONING BY CHEESE. 



Dr. H. L. Westrumb of Hameln, found that seven persons were 

 poisoned by decayed or damaged cheese (fromage passe, Jromage gate). 

 M. Sertiirner analysed this cheese and found in it a peculiar acid, 

 which appeared bo'th to him and to M. Westrumb to be the poison- 

 ous principle ; the analysis was performed with ether and alcohol. 

 Three different substances were obtained from the cheese : viz. 



1st. Caseate of ammonia. 



2dly. An acid fatty, or resinous cheesy, matter. 



3dly. An acid but less fatty matter. 



These substances, tried separately upon dogs and cats, showed that 

 the first was the least poisonous, the third more so, and the second 

 the most poisonous of all. The symptoms occasioned by the poison 



* This (le[)osit, well washed and treated while hot with solution of car- 

 bonote of potash, yields a liquid, from wiiich a large quantity of uric acid 

 may be precipitated by excess of nmriatic acid. 



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