ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 523 



quite cold the mass is divided into pieces and preserved in a stoppered 

 bottle. This glassy mass, of a greenish-yellow colour, is what the author 

 calls the first degree, and its index of refraction is = 2-1203 or 2-12 

 according to calculations made by the firm of M. Zeiss. 



On heating for a longer time the mass thickens and the index = 2-2534 

 or 2 • 25. During the preparation of the object a part of the sulphur volati- 

 lizes and when properly heated the index may be 2-4. The two products 

 may be used indifferently but both, especially the second, are difficult to 

 melt. If so desired they may be dissolved at the time of using in a little 

 bromide of arsenic, but then the same inconveniences may arise as from 

 Smith's original medium, 



Liquidambar prepared according to the author's formula is obtainable 

 from M. P. Rousseau of Paris. Samples of the liquidambar show that the 

 mass is hard enough to fix the cover-glass without the aid of cement. It is 

 used either in its firm condition or previously dissolved in a mixture of 

 alcohol and chloroform. Liquidambar, like storax, is unalterable with 

 age ; it allows structural details invisible in balsam to be clearly seen, and 

 it may be used for histological objects as well as for diatoms. Bacteria 

 mounted in storax or liquidambar show infinitely better than in Canada- 

 balsam. 



Fixing Sections.* — Mr, H. E, Summers writes that the method of 

 fixing sections to the slide, as recently given by him,f has been found to be 

 needlessly complicated when used for celloidin sections. The following 

 simpler method is recommended. 



Place the sections in 95 per cent, alcohol for a minute or two, arrange 

 on the slide, and then pour over the sections sulphuric ether vapour, from a 

 bottle partly full of liquid ether. The celloidin will immediately soften 

 and become perfectly transparent. Place the slide in 80 per cent, alcohol, 

 or even directly into 95 per cent, if desired. The sections will be found 

 to be firmly fixed and may then be stained, cleared, &c. 



Neat method for Rimming Microscopical Preparations.^ — Dr. A. 



Hansen, after alluding to the difficulty experienced in rimming round the 

 cover-glass of preparations mounted in glycerin with the usual varnishes 

 or lacs, states that the difficulty is easily overcome if the edge of the cover- 

 glass be first run round with glycerin jelly which mixes easily with any 

 superfluous glycerin. When cool the jelly allows a further coat of any 

 varnish : the neatest is dammar. 



Brown, J. F.— Mounting Opaque Objects. 



[3 X 1 in. strips of heavy cardboard -witli a central hole 3/8 in. in diameter. 

 " The object to be mounted is placed over the hole of one strip, and then a second 

 strip is placed over the first and secured to it, thus iirmly holding the object 

 between them."] 



A7ner. Mon. Micr. Journ., VIII. (1887) p. 73. 

 Codling, W. E. — Notes on Mounting, 1. Materials. 



Wesley Naturalist, 1887, pp. 81-2. 



Feazer, a. — 'On a simple form of Self-centering Turntable for ringing Microscopic 



Specimens. 



[(1) Much larger and heavier than usual, so that slides which have the specimen 



mounted not in the middle of the slide will not project beyond the edge of the 



disc when being ringed; (2) the springs are made with a special form of 



" washer," so that these (the springs) may be turned freely in any direction ; 



(3) the turntable is provided with a simple arrangement, consisting of three 



screws,, which are placed in such positions upon the table that slides either 



* The Microscope, vii. (1887) p. 73. f See this Journal, 1886, p. 544. 



X Zeitschr. f. Wiss. Mikr., iii. (1886) pp. 482-3. 



2 M 2 



