602 SUMMAEY OF CUIIEENT RESEARCHES RELATING TO 



preparation, where they are allowed to remain for one minute. It is 

 tben quickly washed in water, and in preparations thus treated the 

 bacillus is stained dark red aud its capsule bright red. The staining of 

 the capsule vanishes if left too long in water. 



Staining Tubercle Bacilli on Slides.* — The slide-method, says Dr. 

 Schill, offers several advantages over the cover-glass method for staining 

 bacilli. On account of its larger surface, larger areas of the same or of two 

 to four different kinds of sputum can be simultaneously stained, decolor- 

 ized, and after-stained. For examining the same sputum, only one cover- 

 glass is needed, and this, when the first part of the sputum has been 

 gone over, is pushed down the slide about the distance of the breadth of 

 the cover by just running a droplet of water on to the edge of the cover- 

 glass. In examining different sputa upon the same slide, the cover-glass 

 is withdrawn after each examination, and wiped carefully before being 

 placed upon the second sputum, &c. If a permanent preparation of the 

 sputum is not required, the cover-glass should be cleaned in spirit 

 directly the examination is over. Slides covered with sputum can be 

 kept even without a cover-glass, if protected from dust, and are labelled. 

 If repeated examination be required, a permanent preparation is made, 

 or the slide made be examined anew with the cover-glass and drop of 

 water. Owing to the greater thickness of the glass, heat is given off 

 much more slowly after tLe slide has been drawn thrice through the 

 flame. Hence the Ziehl-Neelsen solution need not be warmed if the 

 staining solution be dropped on the slide while it is still hot. 



With this method, nine or ten colonies from a plate cultivation can 

 be examined at the same time. 



C5) Mounting-, including Slides, Preservative Fluids, &c. 



New Medium for Mounting Pollens and Starclies.| — Mr. A. P. 

 Brown writes, that having experimented with all the various media 

 recommended for the purpose, he has finally adopted the following for 

 permanent mounts of pollens and starches : — I^ Selected gum arabic, 2 oz.; 

 glycerin, distilled water, each 1^ fl. oz. ; thymol, 1 gr. These are all 

 placed in a wide-mouthed bottle, which is corked carefully to exclude dust, 

 and placed in a warm situation. It takes several days to effect a perfect 

 solution, the mixture being stirred up occasionally. When all is dis- 

 solved, strain through linen, and set aside the liquid about a week 

 longer to get rid of air -bubbles, and to allow any small particles that 

 may have passed through the strainer to settle to the bottom ; or it can 

 be filtered through absorbent cotton by using a funnel for hot filtration, 

 which consists of a double tin case holding water, kept at the required 

 temperature by a spirit-lamp placed under the projecting arm. A glass 

 funnel fits inside the hot water-bath, a plug of absorbent cotton is 

 placed in the funnel, and the solution is passed through it. After 

 filtration it is best preserved in compressible tubes. The medium is the 

 suggestion of M. Charles Bulloch, the well-known Chicago optician 

 and microscopist. 



Rest for Slides and for Cultivation Plates.| — M. L. Malassez makes 

 his rest for slides entirely of metal. It consists of two uprights united 



* Ceutralbl. f. Baktcriol. u. Parasitenk., v. (1889) p, 340. 



t Ht. Louis Med. and Surg. Journ., Ivi. (1889) pp. 288-9, from ' American 

 Jourual of Pharmacy.' % Arch, de PhysioL, viii. (1886) pp. 275-7 (1 fig.). 



