POWDERED DRUGS AND FOODS. 713 



c. Plant tissues in addition to starch. — Continued. 



jS Soluble or- swelling in cold water to form a sticky mass. 



Starch and fragments of ducts 250. Tragacantha 



B. Without starch. 



a. Calcium oxalate present. 



Raphides o.i to i mm 251. Scilla 



b. Calcium oxalate wanting. 



Characteristic lignified hairs 252. Nux Vomica 



Characteristic stone cells 253. Almond 



II. Absence of Plant Tissues. 



A. Soluble in water. 



Forming a mucilage with water 254. Acacia 



Monoclinic prisms 255. Saccharum 



B. Insoluble in water. 



a. Soluble in alcohol. 



Irregular fragments 256. Camphora 



b. Insoluble in alcohol. 



" Reddish color with sulphuric acid. 



Gritty ; monoclinic prisms of various sizes. 



257. Saccharum Lactis 

 /3 No color reaction with sulphuric acid. 



1. Soapy feel. 



Broken crystals 258. Talc 



2. Soluble in acetic acid. 



* With efifervescence. 



In prisms or irregular angular fragments. 

 259. Precipitated Calcium Carbonate 

 An amorphous powder . . . 260. Prepared Chalk 

 Rhombic crystals or irregular fragments. 



261. Barium Carbonate 

 ** Without effervescence. 



Rounded masses 262. Heavy Magnesia 



Very light 263. Light Magnesia 



3. Insoluble in acetic acid. 



* Soluble in nitric acid. 



Tetragonal or cubical crystals. 



264.Precipitated Calcium Phosphate 



Acicular crystals 265. Calcium Sulphate 



Rhombic prisms or crystals of various sizes. 



266. Barium Sulphate 



Irregular fragments 267. Terra Alba 



