SPICES. 165 



standard works on these subjects, and also a set of standard samples of all the 

 materials likely to be encountered.** 



(a) APPARATUS. 



(1) Dissecting microscope or hand lens. 



(2) Compound microscope provided with 5 and J inch objective, 1 and 2 inch 

 oculars, double nosepiece, eyepiece micrometer, and polarizing apparatus. 



(3) A series of sieves with meshes ranging from 0.2 to 2 mm. 



(4) Slides, cover glasses, needles, scalpels, forceps, etc. 



(b) MICRO-REAGENTS. 



Of the numerous reagents employed in histological work the following are 

 most useful in spice examination : 



(1) Distilled water. 



(2) Glycerin, pure and diluted with equal volume of water. 



(3) Absolute alcohol. 



(4) Ether. 



(5) Ammonium hydroxid. 



(6) Potassium hydroxid (5 per cent). 



(7) Chloral hydrate (8 parts in 5 parts of water). 



(8) Schultze's macerating mixture. Crystallized potassium chlorate mixed 

 with nitric acid as needed. 



(9) lodin in potassium . iodid. 0.05 gram iodin, 0.2 gram potassium iodid, 

 and 15 cc water. 



(10) Chlorzinc iodin. Dissolve 100 grams of zinc chlorid in 60 cc of water 

 and to this add 20 grams of potassium iodid and 0.5 gram of iodin crystals. A 

 few crystals of iodin should be left in the bottle to insure saturation. Allow 

 the solution to stand a few hours before using. Chlorzinc iodin prepared in 

 this manner will keep for months. If the color developed in the tissue is too 

 deep a blue a very slight dilution of the reagent is advisable. 



(11) Millon's reagent. Dissolve metallic mercury in its weight of con- 

 centrated nitric acid, add an equal volume of water, and decant off the clear 

 liquid as soon as the precipitate settles. 



(12) Ferric acetate or chlorid solution. 



(13) Alkanna tincture diluted with an equal bulk of water. 



(14) Aqueous solution of safranin. 



(15) Hydrochloric acid (10 per cent). 



(16) Acetic acid. 



(c) PREPARATION OF THE SAMPLE. 



Reduce one portion to a fine powder in a mortar. Separate another portion 



into several grades of fineness in sieves of different mesh or by jarring on a 



sheet of paper. In the coarser grades fragments of a suspicious nature may 



of teii be seen with the naked eye or under a simple microscope ; these should 



! be picked out for subsequent examination under the compound microscope. 



The following works are especially recommended : Winton, Microscopy of Vegetable 

 ! Foods, 1906, New York: Moeller, Mikroskopie der Nahrungs- und Genussmittel aus dem 

 i Pflanzenreiche, 1905. Berlin ; Vogl, Die wichtigsten vegetabilischen Nahrungs- und 



Genussmittel, 1899, Berlin ; Tschirch und Oesterle, Anatomischer Atlas der Pharmakog- 



nosie und Nahrungsmittelkunde, 1900, Leipzig. 



