POWDERED DRUGS AND FOODS. 797 



parent. On treatment with citric acid, ammonium hydrate and 

 sodium phosphate, the cr3'stals of ammonium-magnesium phos- 

 phate in glycerin mount are large, star-shaped, and look like 

 snow crystals. 



3. Insoluble in Acetic Acid. 



* Soluble in Nitric Acid. 



If necessary, in deciding on any of the next four powders, they 

 are to be fused with potassium carbonate or sodium carbonate, 

 and a regular qualitative chemical separation effected. 



264. CALCII PHOSPHAS PR^CIPITATUS.— In glycerin 

 mount alone small tetragonal and cubical crystals are observed. 

 If to a few milligrams of the powder on a slide a few drops of 

 nitric acid are added, and then a small quantity of ammonium 

 molybdate solution, stirring well with a glass rod, small, yellow, 

 diamond-shaped crystals are observed, which are permanent in 

 glycerin mounts. 



265. CALCII SULPHAS. — In glycerin mount alone needle- 

 shaped crystals, or long crystals in masses which look like a group 

 of sclerenchyma fibers, are observed. The flame test with plat- 

 inum wire gives bright reddish-yellow. 



266. BARIUM SULPHATE.— In glycerin mount alone 

 irregular-shaped crystals varying in size are observed. The flame 

 test is green. 



267. TERRA ALBA. — This powder is composed of alumi- 

 num silicate and magnesia and occurs in irregular masses. 



