SPICES AND CONDIMENTS. 203 



METHOD OF EXAMINING PEPPERS MICROSCOPICALLY. 



As a preliminary the sieve examination, already mentioned, is of 

 value, the coarser particles left upon a 40 or 60 mesh sieve frequently 

 revealing the nature of the adulterant or the too large proportion of 

 pepper husk. Afterwards it is well, with a good dissecting microscope 

 and a power of 15 to 30, to sort over the ground pepper, and judge of 

 the frequency of the occurrence of the coarse particles, which after a 

 little experience there will be no difficulty in doing. The presence of 

 sand or a notable excess of P. D. can also be detected and estimated in 

 this simple way. Backgrounds of white and black, with reflected light 

 and afterwards transmitted light, may be used in the manner so con- 

 veniently afforded by Zeiss's stand, made for this purpose. 



A portion of the powdered pepper or the separated coarse particles 

 should also be treated with chloral-hydrate solution for twenty-four 

 hours, +o render it more transparent for examination with higher pow- 

 ers, and in the mean time the coarse particles sieved from the powder 

 may be examined under a one and a one-half inch objective, and then 

 crashed and re-examined, using both plain and polarized light. In 

 this way husky matter may bo distinguished and foreign starches 

 detected. Polarized light is then the means of bringing out more 

 plainly the starches, the proportion of which iodine will reveal, mak- 

 ing due allowance for the small granules of pepper starch and all op- 

 tically active tissue, such as the bast fibers and sclerenchyma or stone 

 cells, which are found in olive-stones and cocoa nut shells. 



The structure of the pepper itself, as has been explained, is so char- 

 acteristic as not to bo readily confused with foreign matter. In the 

 chloral hydrate preparation, which should now be examined, much of 

 this disappears as the starch is much swollen by this reagent. The 

 husky matter present is rendered thereby so much clearer on the other 

 hand that its identification and differentiation is made much easier, and 

 it is here that the possibility of fixing the source of the adulterant will 

 often lie. 



Experience with a half dozen samples from a cheap grocery in com- 

 parison with a laboratory sample of pure pepper will soon teach one the 

 best means of making out what has been briefly described. 



It has also been found most valuable to digest about a. gram of pep- 

 per with nitric acid, sp. gr. 1. 1, and chlorate of potash for several hours, 

 or until the color is bleached. It is then possible to distinguish the 

 denser cellular structure more easily than in any other way, particu- 

 larly the stone cells which make up the larger part of the cocoanut 

 shells and ground olive stones, especially with polarized light, being 

 careful not to confuse the stone cells of the pepper husk with those of 

 olive stones or other adulterants. Charcoal at the same time remains 

 unbleached. 



To determine the merits and correctness of the various chemical pro- 

 cesses and statements in regard to them previously referred to, a series 



