90 THE AMERICAN MONTHLY [April, 



sawdust flavored with the oleroesin of pepper. A glance at the 

 mixture under the microscope revealed its true nature. In coarse 

 powders it is sometimes possible to recognize the stomata of 

 leaves. 



d. Pharmacognacy. or the recognition of drugs, is studied by 

 aid of a system based upon the physical characteristic of the sub- 

 stances. As an example, we study the structure and characteristics 

 of a leaf, which is one of the subdivisions of that great class of 

 drugs derived from the vegetable kingdom. Leaves are again 

 subdivided into two kinds, the herbaceous and coriaceous. These 

 two classes are readily distinguished from each other by an exami- 

 nation without the aid of the microscope. However, the case 

 differs when we Come to the study of several other subdivisions 

 of vegetable drugs. For instance, we take the roots, which is a 

 subdivision corresponding to the leaves. The roots are divided 

 into two similar subdivisions, known as the mono-cotyledonous 

 and the di-cotyledonous. It is by means of examining a trans- 

 verse section of these roots under the microscope that the phar- 

 macist determines to which subdivision they belong. The di- 

 cotyledonous are again subdivided into woody, with thick bark ; 

 woody, with thin bark and fleshy roots. As is readily understood, 

 this classification is based solely upon characteristics revealed In 

 the microscope. To continue with the subdivision one step fur- 

 ther, we have the w'oody roots with thick bark, divided into those 

 with oil. resin, or latex ducts and those without oil, resin, or latex 

 ducts. 



The adwmtage of such a system of classification is an inter- 

 esting subject, but does not directly concern us as microscopists. 

 Its consideration usually occupies an entire lecture in the College 

 of Pharmacy. 



c. The use of the microscope in microchemistry is not advanced 

 as far in pharmacy as the use of the instrument in vegetable his- 

 tology. The principal reason for this is owing to the difiiculty 

 of studying crystallography. A few of the more common salts 

 like the cinchona alkaloids have been studied and their micro- 

 chemical appearance are figured in the dispensatories. I have 

 no doubt that microchemistry applied to pharmacy will be greatly 

 advanced by the active pharmacist of the future. 



f. The introduction of the compound microscope in the exami- 

 nation of urine is by no means recent. The value of the instru- 

 ment in this work is so thoroughly recognized that it does not 

 admit of debate. The examination of urine as a part of a phar- 

 macist's work is fast gaining a similar position. 



g. In conclusion, there are many incidental uses for the com- 

 pound microscope in a drug-store. Siich as the examination oi 

 the smaller insects which infest drugs, the study of moulds which 

 are found in pharmaceutical preparations, and other uses which 

 suggest themselves to .pharmacists with an investigating turn of 

 mind. 



