320 METHODS OF ANALYSIS [Chap. 



(C) Ether. 



(d) Ammonium hydroxid. — The concentrated solution, containing about 30% of 

 ammonia gas, is used in making Schweitzer's reagent and for some other purposes. 

 For the turmeric test the concentrated solution should be diluted with 10 parts of 

 water. 



(e) 5% potassium hydroxid solution. 



(f) Chloral hydrate solution (8 to 5). 



(g) Schultze's mixture. — Crystallized potassium chlorate mixed with nitric acid 

 as needed. 



(h) lodin-potassium iodid solution. — A solution of 0.05 gram of iodin, 0.2 gram 

 of potassium iodid in 15 cc. of water. 



(i) Chlor-zinc iodin solution. — 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 and allowed to 

 stand a few hours before using. The chlor-zinc iodin solution, pi-epared 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. 



(j) Millon's reagent. — Prepare as in XV, 9. 



(k) 1% ferric acetate or chlorid solution. — Freshly prepared. 



(1) Alkanna tincture. — Macerate 20 grams of alkanet root for several days with 

 100 cc. of alcohol. 



(m) Aqueous safranin solutioyi. 



(n) 10% hydrochloric acid. 



(O) Acetic aad.— Glacial or 99% acetic acid diluted with 2 parts of water. 



20 APPARATUS. 



(a) Dissecting microscope or hand lens. 



(b) Compound microscope. — Provided with | and I inch objectives, 1 and 2 inch 

 oculars, double nosepiecc, eyepiece micrometer and polarizing apparatus. 



(C) Sieves. — A series of sieves with meshes ranging from 0.2-2 mm. 

 (d) Slides, cover-glasses, needles, scalpels, forceps, etc. 



21 PREPARATION OF SAMPLE. 



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

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

 paper. In the coarser grades, fragments of a suspicious nature may often be seen 

 with the naked eye or under a simple microscope; these should be picked out for 

 subsequent examination under the compound microscope. 



22 EXAMINATION. 



Mount a small quantity of the ground sample in water and examine under the 

 compound microscope with both ordinary and polarized light. This gives general 

 information as to the nature of the material and serves for the detection and iden- 

 tification of starch granules and various tissues. Draw a small drop of the iodin- 

 potassium iodid solution into the same preparation by means of a piece of filter 

 paper placed on the opposite edge of the cover-glass and examine. Starch gran- 

 ules will be colored blue or blue-black, cellulose j^ellow, and proteins either brown 

 or yellow. 



In the manner just described draw a little of the 5% potassium hydroxid solution 

 under the cover-glass and again examine. This treatment gelatinizes the starch 



