226 THE AMERICAN MONTHLY [October, 



objects. Among these we have the various fibres, such as wool, silk, 

 cotton, and linen ; everv microscopist should be able to identify each 

 one of these fibres. Small seeds, hairs, and even the dust which col- 

 lects in a room, are suitable for study. When it comes to less fiimiliar 

 objects, we have various kinds of starch grains, powdered drugs, and 

 other substances which require no section cutting in order to be ex- 

 '(imined. 



It is not advisable to attempt the preparation of permanent mounts 

 for the microscope until the student becomes quite familiar with the 

 examination of objects. By this time another work ^vill prove of service 

 to the pharmacist, and that is The Practical Microscopist, by Davis 

 ($2.1^0). As a guide in the study of powders, I call attention to articles 

 by Hans Wilder, entitled "Microscopical Examination of Powders" 

 (yAtnerican Journal of Pharmacy), June, '90, page 278; July, '90, 

 page 332. Another source of valuable information on the subject is 

 Bulletin No. 13, issued by the Division of Chemistry of the Department 

 of Agriculture ; parts I to V, are of interest to pharmacists, but it is part 

 II that treats of the examination of powders. The bulletin is entitled 

 " Food and Food Adulteration," and can be obtained by addressing the 

 Secretary. 



If the student can aftbrd the expense of a polariscope (which costs 

 from twelve to twenty dollars, and which can be used with the seventy- 

 five-dollar outfit), it is advisable to pvu'chase one at this stage in his 

 study. The polariscope is especially serviceable in the examination of 

 starch grains, crystals, and many other substances. 



The student is now ready to mount specimens for examination and 

 preservation. It is best to commence with the preparation of dry 

 mounts, such as are made with the use of paper covers. Then come 

 dry mounts with the use of cements. A turn-table is essential to the 

 outfit of any one who prepares permanent mounts ; it not only enables 

 him to make more elegant preparations, but saves time and trouble. 

 After learning to prepare dry mounts, the use of balsam, both hard and 

 soft, is in order. Those who have access to the Companion to the U. 

 S. Pharmacopoeia will find the chapter on the subject of Microscopy 

 verv instructive when they come to the use of balsam, glycerine jelly, 

 or glvcero-gum, and other mounting media which require similar tech- 

 nique. The use of balsam should be studied before passing on to 

 mounts made in liquids. The latter is more diiticultthan the foregoing 

 media. Glycerine, carbolic acid, and creosote water, castor oil and 

 other liquids used in mounting, all require about the same work, and 

 can be studied together. 



After gaining proficiency in mounting specimens, the student should 

 take up section-cutting. It is best to commence with free-hand work, 

 such as cutting soft vegetable tissues imbedded in elder-pith. It is very 

 convenient to be able to make such sections, and sometimes circum- 

 stances are such that it is necessary to make them free-hand with a 

 razor, or not at all. If the student does not practise this before he com- 

 mences the use of the Microtome, he will never learn the art. An 

 ordinary potato is a very good substance to practise upon for free-hand 

 section-cutting. The first work of the Microtome should be on such 

 substances as rhizomes of ginger, calamus, podophyllum, etc., which 

 can be imbedded in parafiin or similar imbedding substances. 



