ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 519 



Freeborn, G. C. — Notices of New Methods. II. 



[Celloidin-paraffin imbedding and carmine staining (Kultschizky). New 

 staining medium (Plattner.)] 



Amer. Hon. Micr. Journ., IX. (1888) pp. 52-3. 



Hvass, T. — Om nyare fargningsmethoder vid histologiska studier af nerwafnad. 

 (On new staining methods in the histological study of nerve-tissue.) 



Bygeia, XLIX. (1887) p. 50. 



Lennox. — Beobachtungen iiber die Histologic der Netzhaut mittels der Weigert- 

 schen Farbungsmethode. (Observations on the histology of the retina by meana 

 of the Weigert staining method.) Graefe's Arch. f. Ophthalm., XXXII. (1887). 



Lindner, P.— Gefarbte Hefenpraparate. (Stained yeast preparations.) 



Wochenschr. f. Brauerei, 1887, p. 773. 

 Souza, A. de. — De la pyridine en histologic. (On pyridine in histology.) 



C.R. Soc. Biol., IV. (1887) No. 35. 



(5) Mounting-, including- Slides, Preservative Fluids, &c. 



Medium of High Refractive Index.— Mr. Arthur E. Meates, who 

 has been for more than two years past experimenting upon Prof. Hamilton 

 L. Smith's,* and other media of high refractive indices, considers the 

 following to be his most successful result : — 



Put into a 4-in. test-tube 71^ grains of bromine, add 28^ grains of 

 sulphur, and warm gently until combined; then add 67 grains of freshly 

 sublimed arsenic by very small portions at a time, otherwise the violent 

 action which takes place between the bromine and arsenic will cause the 

 mixture to boil over. After about 20 grains have been added this violent 

 action ceases, and then the rest of the arsenic can be put in at once. 

 When the whole of the arsenic is added, boil gently until it is completely 

 dissolved, which will take about fifteen or twenty minutes. While boiling 

 care must be taken that the vapours of bromide of arsenic (which can 

 be seen mounting up the tube) do not escape. If properly made, thin 

 films of the medium, when cold, will be of a pale-yellow colour. Its 

 refractive index is high, considerably above that of phosphorus. It 

 melts at about 200° Fahr. 



For mounting, the medium should be warmed till it is quite liquid, 

 a small portion taken out on a glass dipping-rod, dropped on a warm 

 slide, and, while soft, the cover with the diatoms pressed upon it. When 

 cold, the superfluous medium may be scraped away and the mount 

 ringed with copal or any other varnish that does not contain alcohol. 

 Hitherto, it has shown no signs of deliquescence or crystallization, 

 although put to most severe tests. 



The medium is practically orpiment dissolved in bromide of arsenic ; 

 but this solution cannot be effected satisfactorily, except by combining 

 the substances while in a nascent condition. It can, however, also be 

 made by dissolving the proper proportions of sulphur and arsenic in a 

 certain amount of bromide of arsenic. It differs from Prof. Smith's 

 medium, which is stated to be "realgar, the transparent sulphide of 

 arsenic, dissolved in bromide of arsenic by aid of heat " ;* realgar being 

 A6 2 S 2 , and orpiment As 2 S 3 . 



Wax Cells.j — Dr. Taylor in describing his method of making wax 

 cells, says that much complaint has been made about these cells on 

 account of their becoming " foggy." This may occur if cells are 



* See this Journal, 1885, p. 1099. 



t Report of Proceedings at Washington Microscopical Society. Cf. Engl. Mech., 

 xlvii. (1888) p. 2». 



