SPICES AND CONDIMENTS. 153 



In pepper and in mustard the parenchyma cells are prominent in the 

 interior portion of the berry, while those constituting the outer coats 

 are indistinct from their deep color in the pepper, but in the mustard 

 characteristic of the particular species. In fact, in many of the spices, 

 especially those which are seeds, the forms of the epidermal cells are ve'ry 

 striking, and even if no attempt is made to classify them their peculiari- 

 ties must be carefully noted, as the recognition of the presence of for- 

 eign husky matter depends upon a knowledge of the normal appearance 

 in any spice. The fibro- vascular bundles are most prominent in ginger 

 and in the barks, where in the powdered spices they are found as stringy 

 particles. 



The sclerenchyma or stone cells, are commoner in the adulterants, es- 

 pecially in cocoannt shells, where may also be seen numerous spiral cells 

 and in the exterior coats fibrous tissue. 



As aids to distinguishing these structures, the following peculiarities 

 may be cited. 



The stone cells and fibrous tissue are optically active and are there- 

 fore readily detected with polarized light, shining out in the dark field of 

 the microscope as silver white or yellowish bodies. 



The fibro- vascular bundles are stained deep orange brown with iodine, 

 owing to the nitrogenous matter which they contain, while parenchyma 

 is not affected by this reagent aside from the cell contents, nor has it 

 any action on polarized light, remaining quite invisible in the field with 

 crossed prisms. 



STARCH. 



Aside from the cellular tissue, starch is the most important element 

 in the plant for the analyst, audits peculiarities will* be considered quite 

 fully. 



It possesses an organized structure and is distinguished by its reac- 

 tion with iodine solution, with which it strikes a deep blue or blackish 

 blue color, varying somewhat with different kinds of starch and with 

 the strength of the reagent. 



Conversely its absence is marked by no blue color under the same 

 circumstances. Heat, however, as in the process of baking, so alters 

 starches, converting them into dextrine and related bodies, that they give 

 a brown color with iodine instead of a blue black. They are then in 

 fact no longer starch, although their form, often not being essentially 

 changed, permits of their identification. 



Although a practical experience in recognizing the starches by these 

 characteristics is essential for their rapid detection when occurring as 

 adulterants, a valuable guide may be supplied to a certain extent by 

 artificial classification s 5 such as Vogel, Muter, and Blyth, after Tripe's 

 work, have arranged. 



VogePs and Muter's are based on the form and size of the granules, 

 of the hilum or central depression or nucleus and the prominence and 

 position of the rings. Tripe showed that with polarized light and 



