1899] MICROSCOPICAL JOURNAL. 317 



bodies apple green, and the bacteria purple (if gentian vio 

 let be used in the Gram's solution). — Knowledge. 



MICROSCOPICAL MANIPULATION. 



Removing Air Bubbles From Microscopic Mounts. — B. 



S. Proctor tells in the Pharmaceutical Journal of a simple 

 method he has sometimes found useful for removing air 

 bubbles in mounting microscopic objects. The method is 

 thus described : "Take a small syringe of the well-known 

 pattern having- a glass barrel, vulcanite mounts and leather 

 packing to the piston. These usually work so nearly air- 

 tight that if the piston be drawn up while the nozzle is 

 closed with the finger it will spring back to its original po- 

 sition. Unscrew the top and remove the piston, close the 

 nozzle with a fragment of beeswax, and half fill the barrel 

 with water : into this drop the section or tissues to be 

 treated. Then replace the piston and screw on the top. 

 The syringe being inverted and the plug of wax removed, 

 the air is to be driven out of the barrel by raising the pis- 

 ton till the water begins to flow out of the nozzle, close the 

 aperture with the finger and lower the piston. A partial 

 vacum is thus formed, and the air rapidly escapes from the 

 cells of the tissue, collecting in the point of the syringe. 

 By removing the finger and raising the piston, the libera- 

 ted air is forced out ; this may be repeated several times 

 so long as air is given off. The same mode of operating 

 is applicable to objects to be mounted in Canada balsam if 

 oil of turpentine be used instead of water and the objects 

 to be mounted are quite dry before immersion in the tur- 

 pentine." 



Double Staining. — Ziemann proposes (Centralhalle fur 

 Bact.) an elaboration of Romanowski's staining process, 

 by which chromatin is colored carmine-red, or carmine- 

 violet, and protoplasm blue. The author uses a mixture 

 of a 1 per cent methyl blue solution, 1 part, with 0.1 per 

 cent eosin solution, 6 parts. The staining is performed in 

 concave well slides, which are covered to avoid evapora- 



