THE MICROSCOPE. 157 



Carborundum. — This new compound is made from carbon, 

 sand and salt, but it is composed of silicon 69 per cent, carbon 

 30, impurities 1 per cent. Under the microscope it exhibits 

 crystals of a blue color, but with some of a yellow-green color, 

 some black, and some white. Mr. Hagen has kindly favored us 

 with some specimens of this new crystal. 



To a limited number of subscribers we can mail enough 

 to make a few mounts, and to all our contributors who so desire 

 we shall take great pleasure in sending samples. 



QUESTIONS ANSWERED. 



Note. — Dr. S. G. Shanks, of Albany, N. Y., kindly consents to receive all sorts of ques- 

 tions relating to microscopy , whether asked by professionals or amateurs. Persons of aL 

 f ades of experience, from the beginner upward, are w koine to the benefits f this depart- 

 ment. The questions are numbered for future reference. 



169. — Describe fully how to stain bacilli to show spores, flagellae and 

 capsules. — En quirer. 



Lceeffler's method is best for flagellar Take 21 drams of 20 

 per cent solution of tannin in water, add H drams of a cold sat- 

 urated solution of sulphate of iron and 16 drops a saturated so- 

 lution of fuchsin, or of methyl blue, in water and mix well. Just 

 before using, add 16 minims of a 1 per cent solution of sodium 

 hydrate. This is the mordant. 



The staining fluid is a saturated solution of fuchsin in aniline 

 water. Add about 20 drops of a 1 per cent solution of sodium 

 hydrate to 4 oz. of the stain. 



The cover glass should be prepared from a pure culture be- 

 cause albuminous material will be stained also and obscure the 

 delicate flagellar Pass the film lightly through a flame, flood 

 with the mordant, heat until steam arises, and wash thoroughly. 

 Flood with the stain and steam as before, let the stain act for 

 one minute, wash thoroughly, dry, and mount in xylol bal- 

 sam. 



The above aniline-water fuchsin will stain capsules. The 

 prepared cover must be carefully named as above, because the 

 capsules are very easily destroyed. Prepared covers for spores 

 should be rather strongly flamed. Spores are very resistant 

 and are best seen when the bodies of the bacilli are partly des- 

 troyed. Too much flaming will destroy the bacilli so that after 



