MICROSCOPICAL DIAGNOSIS. 9! 



ing the mustard to the light, when it will fade to a dingy yellow. Its 

 presence can also be detected by treating the suspected substance 

 with potassa, and if turmeric be present the substance will turn a 

 deep yellow or brick-red color. The starch grains are quite uni- 

 form in size, and in shape are elliptical, oval, or like flattened discs, 

 sometimes even truncated. The nucleus is at one extremity, and has 

 the appearance of being entirely outside of the grain proper. Rings 

 quite distinct, numerous and uniform in density, pass around the 

 grains like zones, and present a beautiful appearance in a fresh grain. 

 Commercial turmeric has been heated so much in preparation for 

 market that frequently the rings cannot be seen, and even the normal 

 shape of the grain is lost. In the fresh state they show a decided 

 cross or black bands with the polarized light ; but this is seldom seen 

 in commercial turmeric. The coloring material is a deep, reddish 

 yellow, and is contained in special cells of the parenchyma. The 

 starch grains are white. The action of iodine and potassa is the 

 same here as with all starches, but sulphuric and sulphochromic 

 acids are of perhaps more value in this case, for they turn the color- 

 ing matter to a peculiar rose-pink. In the examination of mustard, 

 this test is valuable. Of the twenty specimens of. mustard examined, 

 during the past two years, every one contained turmeric. It is used 

 to color many other spices. The turmeric of commerce is itself 

 adulterated frequently with corn starch, etc. 



Ginger Starch grains are irregularly spherical, oval, or disc- 

 shaped^ closely resembling those of turmeric, belonging to the 

 same family, Zingiberaceae. The nucleus is at the extremity, as if it 

 were hardly a part of the grain, the rings are numerous and uniform. 

 A cross is seen with polarized light. 



Much of the ginger of the market has been scalded, which 

 causes the starch grains to lose their normal shape. It is difficult 

 then to see the rings ; and the cross, which was seen with the polar- 

 ized light, is destroyed. In examining the starch from the root, as 

 found in the stores, the starch grains at the centre will be found to 

 be more perfect than those taken from near the surface of the root.* 



*The following references, furnished by Mrs. Stowell. may be of value to those wishing 

 to carry the study of the starches farther: Hassall's Ik Adulterati ms in Food and Medicine;" 

 Sachs' "Botany," page 56; Sou^erian, "Dictionnaire des Falsifications;" Wiesner, "Robstoffe 

 des Planzenreiches," pp. a^q 289; Planchon, "Determination des Drogues Simples," Vol.11. 

 chap. XIII; Nageli, "Die Starkekorner," Zurich, 1858, 4; Fliickiger und Hanbury's "Pharma- 

 cographia." 



