MEALS, BRANS, ETC. 



143 



As to the microscopic characteristics of ergot, see Klimmer, Hygiene. It is easily 

 distinguished from the grain seed coats, etc., even when unstained. 



In addition to the microscopical examination, spectroscopic examination should 

 be resorted to if necessary. 



Macerate 10 grams of meal for 5 to 6 hours in sulphuric acid-alcohol (10 drops 

 of a 20 percent solution of sulphuric acid in 20 grams of 95 percent alcohol) and 

 filter. Alkalize the filtrate with ammonia, filter and examine with spectroscope. 

 Ergot shows two absorption bands in the green (90 to 99 and 112 to 122) and a 

 blue band (145, when the sodium D-line is at 70 and the Potash a on 26 and potash b 

 on 219). 



7. Very frequently the spores of smut, especially Tilletia caries, occur in wheat 

 and mixed brans, rarely in others. To examine, sift the bran or meal with a % mm. 

 (not more than H mm.) mesh. 



Fig. 76. Rice. Cells of the external covering of the glumes. 



A, Outer seed coat cells treated with caustic potash; A', the same treated with water; t, protuber- 

 ances on same; r, round cell, with hair, h; F, cells of the subjacent fibrous tissue. (After Boehmer.) 



A portion of the sifted material is removed with the tip of a knife blade, moistened 

 with water and examined under a magnifying powder of 50 diameters with open 

 diaphragm. If the material is previously boiled in dilute caustic soda solution, the 

 smut spores become more distinctly visible. If a slide, made from the sifted ma- 

 terial mixed with water, but otherwise untreated, and the material spread just 

 sufficiently thin to permit examination, shows 20 smut spores in a microscopic field, 

 the material is considered of inferior grade (see illustration in Klimmer, Hygiene). 



8. Testing for evidence of spoiling. 



In the examination of vegetable oil by-products, use is made of the iodin-starch 

 reaction (p. 134). After proper preparation of the material, search is made for seed 

 shells, hulls, etc. The fruit hulls and seed coats of oil seeds frequently contain 

 thick-walled bast and stone cells, deposits of tannic acid and characteristic pig- 

 ments. If ricin poisoning is suspected, search is made for traces of castor oil beans 

 (p. 147). 



