ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 673 



off. Dehydrate with anilin oil, clear in xylol, and mount in balsam. 

 The organisms are stained deep purple and the agar a pale green. 



Demonstrating Tubercle Bacilli in the Blood.* — A. Lippmann 

 obtains 10 c.cm. of blood from a vein by means of a syringe. The 

 blood is placed in a flask along with 30 c.cm. of 3 p.c. acetic acid. The 

 mixture is centrifuged for £ to \ hour, and then the supernatant fluid 

 is poured off, while the deposit is treated with water. To the deposit are 

 added 60 c.cm. of 15 p.c. antiformin, and the mixture incubated for 

 \ to 1 hour. The fluid is again centrifuged, and, after washing the 

 sediment twice with water, smears are made, fixed and stained in the 

 usual way. Examination of the films is toilsome, as only a few bacilli 

 are usually present. The author obtained positive results in 11 out of 

 25 cases. 



(5) Mounting - , including- Slides, Preservative Fluids, etc. 



Polyscopic Cell.f — C. S. Banks describes how to make a new 

 microscopical accessory which will be useful to entomologists and also to 

 general biologists. The polyscopic cell is merely a section of glass 

 tubing of small calibre, made by grinding it to the form of a square 

 prism by means of a rock-grinding apparatus. Lengths of glass tubing 

 say 4-6 mm. in diameter, are cut into pieces from say 15-20 mm. long. 

 Nine to a dozen of these are fastened to a small plate of glass by means 

 of a mixture of 20 parts white shellac and 7 parts Canada balsam. This, 

 in the form of a pencil, is applied to the glass plate held over the gas 

 flame, until a sufficient cpiantity has melted upon the plate. The short 

 tubes are then placed close together and pressed down upon the plate 

 so that they will all be parallel. The cement having become hard, the 

 tubes are ground down upon the steel wheel of a rock-grinding machine, 

 the operator employing first coarse emery and then finer until their 

 surfaces have become worn to the desired degree and have the velvety 

 appearance of ground glass. A still finer polish may be obtained by 

 next grinding for a short time on a plate glass with pumice and water. 

 The next step is to dry the plate and gently heat it until the tubes 

 become loose enough for removal. The entire mass of adherent tubes 

 may be slipped off, turned completely over, pressed firmly to the glass 

 plate to remove air bubbles and, after cooling, the operation of grinding 

 the faces on the opposite side begun. This being completed, the tubes are 

 now removed as before, set up on edge so that their plane faces are con- 

 tiguous, re-cemented to the plate and the third face ground. For the 

 fourth face, the mass may be slipped off entire and turned over, the 

 same precautions being taken to press the mass flat to the plate. The 

 cells may now be removed from the plate and, after cleaning off the 

 cement, they are ready for use. They may, however, be polished even 

 more finely if it is so desired, to remove the ground surface and render 

 them perfectly transparent like ordinary glass slides ; but this is not 

 absolutely necessary, for the following reasons : After mounting the 

 specimen, the only thing necessary when it is desired to study it under 

 the Microscope is to place a drop of immersion oil on the top of the cell 



* Muenchen. Med. Wochenschr., lvi. (1909) pp. 2214. 

 + Philippine Journ. Sci., v. (1910) pp. 78-83 (2 pis.). 



