1888.] MICEOSCOFICAL JOUENAL. 203 



Microscopical Examination of Drugs. 



• By Prof. H. M. WHELPLEY. 



In oi-der to examine the structure of a root, tuber, rhizome, stem, wood 

 or bark, the drug should be cut at right angles to the axis. I find a scroll- 

 saw very convenient for such v\^ork, but any small savv^ or sharp knife will 

 answer the purpose. The freshly-cut surface of one of the pieces should be 

 rubbed on sand-paper or a flat file to make it smooth. Some drugs will 

 show the structure, as far as it is described in the Pharmacopoeia, without 

 aid of a microscope. This is especially the case when the cut surface has 

 been moistened. The next step is to soak the drug, or at least the end to be 

 examined, in water until it has swollen to about its natural size. This can 

 be determined by the absence of wrinkles on the surface of the drug. The 

 exact time to thus macerate varies with each drug, and is also influenced by 

 temperature. The danger is in soaking it so long that the soft parenchyma 

 tissue is distorted. The drug should then be transferred to glycerin for a few 

 hours, and it is ready for examination. Place a cover-glass, or a piece of 

 any thin glass, over the cut surface and let it remain by adhesion. Examine 

 by aid of good light, and it will surprise you to see how easily the coarser 

 structure can be determined. 



To examine seeds they must be cut in sections and mounted as described 

 in the various works on pharmacognosy and microscopy. Leaves that can 

 be advantageously studied in this manner are few. Buchu is the only official 

 one that is described microscopically. The appearance of the hairs on digitalis 

 and a few other leaves should be described, as they can thus be distinguished 

 from other leaves accidentally or fraudulently added. The official description 

 is suitable for the entire leaves, but is not sufficient to identify some of the 

 pressed drugs or broken ones found in the market. 



Such drugs as lupulin, lycopodium, etc., must be mounted in glycerin, or 

 some other liquid, after well-known methods. Make it a rule to select good 

 samples of drugs for examination, and become familiar with their structure. 

 The Companion to the United States Pharmacopceia and Maisch's Organic 

 Materia Medica are both valuable works for reference in the study of the 

 structure of drugs. 



Aconitum. — ' Whitish internally, with a rather thick bark enclosing a star- 

 shaped pith, about seven rayed.'* In order to make out this structure, cut a 

 root transversely about midway of its length. Macerate in water for six to 

 twelve hours, and then in glycerin for twenty-four hours. Cover the section 

 with a thin cover-glass, and allow the glass to stick to the drug by adhesion. 

 The structure can be made out with a power often diameters, even by aid of 

 lamp-light. 



Aloe. — '• Mixed with alcohol and examined under the microscope it ex- 

 hibits numerous crystals.' I found several samples of the official (socotrine) 

 variety of aloes that did not show these crystals. In others they appeared as 

 a yellowish-red sediment, the individual crystals not being over twenty-one 

 to twenty-six mici-omillimetres (1-1,2501)1 to i-i ,000th of an inch) long. The 

 best results were obtained by mixing a small quantity of aloes with an equal 

 quantity of alcohol, and examining a thin (250 micromillimetres) film with 

 a i-5th-inch objective and two-inch ocular. Good illumination is essential. 

 As these crystals are of aloin, the drugs that do not show them must be of an 

 inferior quality. Some specimens of Cape and Barbadoes aloes showed 

 much larger crystals, some of them being about 500 micromillimetres (i-5oth 

 of an inch) long. The crystals are all prismatic and easily distinguished 

 from fine particles of sand that are to be seen in the field. There is also oc- 



*The quotations are all from the 6th Decennial U. S. Pharmacopoeia. 



