ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 415 



by which means a triple staining is effected. The technique is as follows : 

 1 grm. of saffron is boiled in lOOc.cm. of water for half an hour and the 

 decoction filtered. In the course of a few days the solution becomes 

 turbid, but retains its staining properties for 2 to 3 weeks. Pieces of 

 tissue are best fixed in Bouin's fluid, but Zenker and sublimate give fair 

 results. The sections are first stained with Mayer's hsemalum. Should 

 the connective tissue be stained, the section must be decolorised in HC1- 

 alcohol. After washing in tap-water the sections are blued in lithium 

 carbonate 1 p.c. ; they are then washed freely to remove all traces of the 

 carbonate, and afterwards stained for 10 minutes in 5 p.c. water-soluble 

 eosin, or for '2 hours or more in 1 p.c. eosin. After a wash in water the 

 sections are treated with the saffron solution for from 5 to 10 minutes. 

 They are then rapidly washed with water, dehydrated, cleared up and 

 mounted in dammar or balsam. The nuclei are blue, protoplasm red to 

 orange red, connective tissue, bone, and cartilage yellow. 



(5) Movmting-, including- Slides, Preservative Fluids, etc 



Fading 1 of Anilin-stained Microscopical Preparations and a New 

 Medium.* — A. C. Coles, after remarking that the greatest cause of fading 

 in balsam-mounted preparations is acidity, whether present at the time 

 or developing subsequently from oxidation of the mounting medium, 

 expresses the opinion that practically all substances of the nature of 

 balsams, oleo-resins, or cedar-oil, will sooner or later oxidize and become 

 acid, and therefore are liable to cause fading of aniline stains. The 

 author was advised to try paraffinum liquidum, or a pure form thereof, 

 viz., parolein, as it was absolutely neutral and remains so. His method 

 of use is as follows : — 



" A small drop of parolein is placed on a perfectly clean cover-glass, 

 which has been held over the flame of a spirit lamp to drive off any 

 moisture on the glass, and this is applied to the air-dried film, which is 

 also held for a second considerably above the flame, just long enough to 

 make the moisture fade off. If the amount of oil is just sufficient to 

 reach the margin of the cover-glass, so much the better. If there be too 

 much oil the preparation is placed under a piece of blotting paper, and 

 the excess of oil removed as much as possible. The margin of the cover- 

 glass is then rung round with Apathy's gum syrup made as follows : 

 picked gum arabic, cane sugar, ordinary, not candied, distilled water, 

 of each 50 grm. Dissolve over a water bath and add 0*05 grm. 

 thymol. I test the reaction with litmus paper, and if acid I add a tittle 

 sodii carbouas. If the cover-glass is round the cement can easily be 

 applied on a turn-table ; if square, which I prefer, one paints it round 

 with a very small brush. The gum syrup sets quickly in a warm room 

 in about 15 to 30 minutes. When dry 1 apply over it a coat of Bell's 

 cement, which also dries quickly (the latter is not acted upon by the 

 immersion oil), and I feel I have a preparation that will keep." 



The writer points out that time alone will show whether the prepara- 

 tions will lie permanent or not. and then remarks that while the mounting 

 is a little more trouble, parolein is optically superior to cedar-oil or 

 balsam. 



* Lancet (1911) i. pp. 878-8. 



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