The Microscope. 303 



For glycerin and its preparations a large number of cements 

 has been recommended. They are of all sorts and colors, and while 

 the majority of them ai'e good, we find, as in the case of mounting 

 media, that three or four of the more tried ones will answer every 

 purpose. 



As for the use of colored cements, there should be but one 

 opinion: with the exception of the more neutral tints, such as black, 

 dark-brown, etc. , their employment is dangerous to artistic success. 

 To obtain a good result, the color of the cement should harmonize 

 with that of the specimen. This the average microscopist seldom 

 thinks of doing. When working with decided colors this harmony 

 is exceedingly difficult to obtain. Do not assume that you have the 

 creative faculty of an artist: you may be a good judge of the artistic, 

 but that does not imply that you can make artistic things. Never 

 use several colors in the same ring. If you must defy all artistic 

 decency, at least confine yourself to the employment of a single 

 color. For example, a heavy blue ring around a specimen stained a 

 bright green should be sufficient to delight the most depraved. When 

 a single color is thus used one has the power to assume that the 

 exhibited depravity, though innate, has at least the merit of being 

 unconscious. But with those elaborate combinations — combinations 

 which exhibit an ingenuity worthy of better things — there can be but 

 one conclusion: the outrage was deliberate. To do justice to such 

 cases requires the pen of an aroused Ruskin. 



Simplicity is not only the safest but truest. One of the safest^ 

 colors for general use is black, and that color is now mostly employed 

 by those whose work is considered to be among the best. Not only 

 does it harmonize, by virtue of its neutrality, with the specimen 

 color, but draws out and develops that color. For a very decided 

 stain, such as a bright carmine, a brownish-black cement will serve 

 to tone it down. And so with the employment of other colors — the 

 effect can be heightened by careful combinations. 



A perfect cement should be durable, firm, smooth, non-contrac- 

 tile, and insoluble in the mounting medium with which it is used. 

 Though no one cement combines all these qualities in the highest 

 degree, those here given will be found to do good service: 



Zinc -White. 



Benzol 8 parts. 



Gum dammar S parts. 



Oxide of zinc 1 part. 



