120 



Journal of Applied Microscopy. 



well mixed powders were placed in a 

 porcelain capsule containing a mixture 

 of alcohol, glycerine, and water, and 

 after two hours' maceration the exami- 

 nation was commenced, when the nature 

 of the elements enclosed in the cells was 

 observed. To render more prominent 

 the form of the various elements and 

 fragments the particles were boiled 

 with alkaline water. Those portions of 

 the structure partially invisible before 

 now became prominent. In the case of 

 Virbunum prunifolium it could be clear- 

 ly seen in the powder that the nu- 

 merous stone cells can readily be dis- 

 tinguished; as regards the opulus the 

 absence of these plainly indentifies the 

 bark as distinguished from the other 

 species. 



a 



Fig. 1. 



Another study on the same line — dis- 

 tinction between Frangula and Cascara 

 barks — resulted in the following: that 

 Rhamus frangula contains no stone 

 cells, while the R. Californica and the 

 R. purshiana contain a large number of 

 these scattered in large irregular groups 

 below the cork and usually outside the 

 region of bast. The presence or absence 

 of stone cells, therefore, was found to 

 be a method by which powdered fran- 

 gula could be distinguished from R. 

 pursiana and R Californica. 



Continuing along this line was an- 

 other investigation which related to the 

 distinction between Senega and Quil- 

 laja, it having been urged that Quillaja 

 bark was sometimes used as an adul- 

 terant of the former. It was found in 

 this study that there was no difficulty 

 whatever in distinguishing between the 

 powders of Senega and Quillaja. In the 

 latter bark are found elements not pres- 

 ent in Senega. The presence of bast 

 fibers, of schlerotic tissue, and the 



numerous and easily observed prismatic 

 crystals of calcium oxalate in the Quil- 

 laja marks this adulterant and betrays 

 its presence, when mixed with senega 

 powder. The elements characteristic of 

 these powders are herewith shown. 



Fig. 1. 



As another examination or study in 

 this line of work, a problem was sub- 

 mitted asking for the detection of Ru- 

 mex hymenosepalous in powdered rhu- 

 barb. This latter kind of adulteration 

 was somewhat new to the writer, and he 

 carefully examined the literature to find 

 where the use of it as an adulterant was 

 first suggested. He found that in "Il- 

 lustrated New Mexico," fifth edition, 

 1885, page 3, was a statement of this kind. 



Fig. 3. 



Speaking of canaigre, it said: "It seemed 

 probable that this root may be used to 

 advantage in place of rhubarb, when a 

 more astringent medicine is indicated." 

 It was found upon examination that the 

 characteristic elements of powdered 

 rhubarb are the calcium oxalate crys- 

 tals and massed acicular crystals of 

 chrysophanic acid, and that the adul- 

 teration of rhubarb with canaigre may 

 be detected by its characteristic long 

 starch grains, as represented. Further- 



