165 



Heated with concentrated sulpliuric acid, it sepai-ates into carbonic 

 acid and oxyd of carbon. Most of the Oxalates are insoluble in 

 water; few of them dissolve in a solution of Oxalic acid or of 

 chloride ammonium; all dissolve in diluted nitric acid, though 

 more sparingly than most of the salts of the other organic acids, 

 "which are by themselves insoluble in water ; the soluble Oxalates 

 precipitate the salts of lime, including the sulphate, from their 

 solutions, except in the presence of an excess of any strong mineral 

 :acid. 



The qualitative and quantitative determination of Oxalic acid 

 is based upon its behaviour towards lime, with which it yields a 

 white, pulverulent precipitate, insoluble in acetic acid, and con- 

 vertible into carbonate of lime at a low red-heat without turning 

 black. As the Oxalic acid generally occurs as Oxalate of lime, it 

 is genex'ally contained in the extract prepared by diluted hydro- 

 chloric acid. See No. vi., Div. iü., Pt. ii. 



Oxyacailtllill=:C32 H23 NOn. Alkaloid, besides berberin in 

 the root bark of Berbei'is vulgaris, and also discovered in another 

 species of Berberis from Mexico, and likely to occur in many other 

 species. Dilute the mother-ley obtained in the preparation of the 

 chloride of berberin with water ; precipitate with carbonate of 

 soda, wash the precipitate with water, treat with hydrochloric 

 acid, filter, precipitate with ammonia, wash and dry the pi-ecipi- 

 tate, draw out with ether, evaporate the solution, treat again 

 with hydrochloric acid, precijntate with ammonia and dry. — Snow- 

 white, amorphous, highly electric powder, turning yellow at the 

 sunlight ; is converted into fine needles by pouring on it a little 

 ether or alcohol ; has a pui'e bitter taste and an alkaline reaction ; 

 loses at 100'' 3'13%; fuses at 139°, and becomes later decomposed; 

 nearly insoluble in water, in 30 parts cold, and in one part boiling 

 alcohol of 90%, in 125 parts cold, and in 4 parts boiling ether, 

 most readily in chloroform, also in oils, in concentrated sulphuric 

 acid with brown-red colour ; liljerates iodine from iodic acid ; 

 combines with acids to mostly crystallisable salts, soluble in water 

 and in alcohol. 



0xyi>iU0taimic Aci(l=Cu Hs Og. Occurring towards mid- 

 winter in the leaves of Pinus sylvestris and allied species. Is 

 obtained in the preparation of pinopicrin (see this) as Oxypinotan- 

 nate of lead. Treat this with diluted acetic äeid, throw down 

 the filtrate with sub-acetate of lead, wash the precipitate, decom- 

 pose with sulplmret of hydrogen, and evaporate the filtered liquid 

 over the watei'-bath. — -A grej^ or brownish powder, inodorous, of a 

 very astringent taste ; dissolves readily in water and in alcohol, 

 precipitates neither glue nor tartarated antimony, imparts a green 

 colour to salts of oxyd of iron. By boiling with diluted sulphuric 

 acid a red powder is foi'med, but no sugar. 



