56 The Microscope. 



infallible, and which requires both time and apparatus. The sim- 

 plest way out of the dilemma is afforded by the microscope, which 

 stands ever ready at hand. But little knowledge of technique is 

 necessary, and little time is lost in applying this important test. All 

 that is essential is that a few shreds of tissue torn apart by needles, 

 or a thin slice, or the powdered article be placed on a slide in a 

 drop of water or glycerine under the instrument. Although the 

 pharmacopoeias and dispensatories of England and America as yet 

 hardly notice this instrument, its importance as a part of the 

 druggist armamentarium is in this country beginning to be recoo-- 

 nized, and at present nearly all our schools of pharmacy include 

 a course of microscopy in their curriculum. 



The demand for mounted slides has been so greatly in excess of 

 what was anticipated, that our stock of several hundred specimens 

 has already been exhausted, and we have not yet been able to fill all 

 orders. All those who have asked for slides, however, will receive 

 them as soon as we can get them out, and we ask for indulgence if 

 we are seemingly slow in so doing. Demands have been made for 

 every variety of object, and some slides asked for would sell for 

 many dollars each. It is quite obvious that we cannot furnish such 

 specimens ; and hereafter we miist request subscribers to allow us to 

 make the selection, and we will guarantee satisfaction. 



We realized that in making this unprecedented offer we were 

 liable to have our hands full, and we are very glad that so many of 

 our friends are availing themselves of it, although, basing our esti- 

 mates on a former circulation, we are somewhat unprepared for the 

 present "rush." No list of slides will be published. 



Mr. B. F. QuiMBY, of Chicago, whose universal slide carrier we 

 noticed some time ago, has devised another useful appliance in the 

 shape of an "illuminator" or lamp shade, to be used with the Griffith 

 Club microscope. This consists of three pasteboard cylinders accu- 

 rately fitted one within the other,— the external revolving on the 

 middle, the inner being removable. All three cylinders are pierced 

 anteriorly by a round aperture; the middle piece having also a slot. 

 AMth the inner cylinder removed, the external piece may be twisted 

 one way or the other, and the pencil of light coming through the 

 opening thus regulated; or, in the examination of diatoms, the slot 

 may be used. The inner surface of the second cylinder is white, but 

 for the convenience of those who prefer a black backgi'ound, the 

 inside of the third cylinder is of that color, and this may be slipped 

 into the illuminator whenever a dark surface is required. 



