QUANTITATIVE MICROSCOPIC DETERMINATIONS 171 



(a) A count of the licorice tissue upon which the per cent, of 

 licorice is based. Is the licorice of the peeled or of the unpeeled 

 variety? 



(b) A count of the sulphur particles present. 



(c) In case anise is used as the flavoring agent, instead of the 

 oil of anise, then a separate count must be made of a pure sample of 

 anise in order that the percentage amount in the compound powder 

 may be ascertained. 



(d) A count of the sugar particles present. 



The reconstructed formula based upon the results of the several 

 counts should be closely similar to that of the actual pharmacopceial 

 percentages composition. 



The microscopes used by the students must be standardized 

 to the same magnification and the same area of the field of view. In 

 each instance it must be stated whether the high or the low power 

 was used in making any given count or set of counts : in most instances 

 the low power will suffice. For making starch counts and counts of 

 similar minute particles, the high power must be used. 



The following is a list of vegetable drugs and spices giving the 

 microscopical characteristics of each substance named upon which the 

 percentage counts are to be based. Where more than one histological 

 element is named, the first is the one considered the most important 

 for the purpose of making the counts. The other elements may be 

 used for check purposes. The structural elements proposed for pur- 

 poses of making the percentage counts, are not necessarily also the 

 more important for purposes of identification, and in many instances 

 that combination of tissues and of tissue elements which will unmistak- 

 ably identify the drug or spice, is of little value for the purpose of the 

 percentage determination. It will be found that some vegetable drugs 

 reveal no special identifying microscopic structures, as belladonna 

 leaves, stramonium leaves, spigelia roots and rhizomes, cypripedium 

 roots and rhizomes, lappa roots, fennel, caraway, and others. For 

 this very reason added adulterants are all the more readily recognized 

 as these usually reveal some distinctive microscopical characteristic. 

 In such cases the percentage counts are made of the adulterants and 

 the result subtracted from the total amount leaving the percentage 

 of the drug or spice itself. Belladonna, for example, is frequently 

 adulterated with phytolacca, and the adulteration is at once recognized 

 by the very characteristic scattering acicular crystals of phytolacca, 

 but these diagnostic structures are of no value for making percentage 

 determinations. On the other hand, ground olive pits which are so 

 frequently used for the purpose of adulterating spices, nut gall and 



