APPENDIX. 



Preservative Media. — The most generally useful 

 medium for mounting microscopic objects is Gum 

 and Glycerine, it is made as follows : — 



In a glass measure, place sufficient clean picked 

 gum arabic, to reach the line marking half an ounce, 

 add cold distilled water to make one ounce. This 

 should be left standing two days and stirred at in- 

 tervals till completely dissolved. The solution is 

 filtered by squeezing it two or three times through a 

 fine linen cloth. One sixth part of a saturated solu- 

 tion of Boracic acid in Glycerine is now added, and 

 the whole placed in a capsuled bottle containing a 

 lump of camphor. 



The formation of air bubbles by filtering and stir- 

 ring is of no consequence, as they disappear com- 

 pletely after a few days. 



Bacillus Tuberculosis. — Dr. Gibbes recommends 

 staining the specimen with Methyline Blue instead 

 of Chrysoidine, the acid being previously removed 

 by frequent washings in distilled water. 



This is a great improvement and if the Bacilli are 

 mounted in Gum and Glycerine instead of Balsam, 

 the reproduction of their appearance by means of 

 photography is rendered comparatively easy. 



