<prompt> Which of the following test shows yellow needle shaped crystals of spermine picrate?Florence testBarberios testTakayamas testTeichmann test  <response>: CHEMICAL METHODS FOR DETECTION OF SEMEN Barberios test Spermine present in semen reacts with picric acid to form yellowish needle shaped crystals of spermine picrate. Florences test Choline from semen reacts with Florence solution potassium iodide iodine distilled water to form brownish rhomboid shaped crystals of choline iodide. CRYSTAL TESTS FOR BLOOD STAINS Teichmann testHemin crystal test: stain extract and few crystals of sodium chloride are taken and heated with glacial acetic acid. If stain happened to be blood, dark brown rhomboid shaped crystals will be formed as visible under microscope. Takayama testHemochromogen crystal test: when bloodstain extract is heated with Takayama reagent Pyridin NaOH glucose distilled water, pink feathery crystals will be visible under microscope. 