ตำรายาของประเทศไทย
Thai Pharmacopoeia
สำนักยาและวัตถุเสพติด กรมวิทยาศาสตร์การแพทย์ กระทรวงสาธารณสุข
Bureau of Drug and Narcotic, Department of Medical Sciences, Ministry of Public Health4.14 CRYSTALLINITY
Use the method specified in the individual monograph.
Method I
To prepare the sample for examination, mount a few particles in liquid paraffin on a clean glass slide. Examine the sample by means of a polarizing microscope. The particles reveal the phenomena of birefringence and extinction positions on revolving the microscope stage.
Method II
To prepare the sample for examination, mount a few particles in liquid paraffin on a clean glass slide, add 1 drop of ethanol, and allow to react for about 30 seconds. Then proceed as directed in Method I.