ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 367 



and remains beyond all others the most suitable for routine purposes. 

 Herman's ammonium-carbonate crystal violet is also an excellent 

 method. In principle it resembles that of Ziehl. The staining mix- 

 ture, however, does not keep well, and has to be made up fresh at short 

 intervals. 



Staining Medullary Sheath of Nerves.* — "W. Gilbert recommends 

 the following method : — Treat with iron alum for 4 to 6 hours. Stain 

 with molybdic acid hematoxylin for 12 hours at dl'^ C, or for 24: hours 

 ■at room temperature. Differentiate in Weigert's sodium ferricyanide 

 borax solution for a period varying from a few seconds to 2 minutes, 

 according to the depth of the stain and the thickness of the section. 

 Wash in tap water. The differentiation must be controlled by micro- 

 scopic examination. 



Cell-staining- in Weigert-Pal Preparations. t^ — For staining gang- 

 lion-cells in such preparations, C. U. Ariens Kappers and I. Ketjen 

 recommend the use of a paracarmine stain (acid carmine 1 grm., alumi- 

 nium chloride 5 grm., calcium chloride 4 grm., dissolved in 100 c.cm. 

 of hot 70 p.c, alcohol). The sections treated by the Weigert-Pal 

 method are soaked for 2 or 3 hours in distilled water containing 5 c.cm. 

 of saturated lithium carbonate solution. Then, after remaining over- 

 night in water, the material is placed in 50 p.c. alcohol (made up with 

 distilled water) for 24 hours, and then placed in a second 50 p.c. alcohol 

 bath. The sections are stained with paracarmine for 5 or 10 minutes, 

 washed in 70 p.c. alcohol, transferred to 9(5 p.c. alcohol, cleared in 

 carbolxylol and xylol and mounted in Canada balsam. 



Staining-cells in Chromicised Material. J — C. U. Kappers, in view 

 of the unsatisfactoiy results obtained with aniline dyes in working with 

 material of this type, has experimented with a number of vegetable 

 dyes. After quoting the work of Claudius and others, he describes his 

 experiences with stain prepared from elderberries. The expressed juice 

 is allowed to ferment for some days, and is then boiled for 10 minutes 

 or so. The addition of 1 p.c. carbolic acid renders this fluid most satis- 

 factory for histological purposes. The method is as follows : — After 

 staining overnight in the carbolized fermentation product, the material 

 is washed, diff'erentiated in 3 p.c. liquor ferri sesquichlorati, washed, 

 dehydrated and mounted. Good preparations of cells and axis-cylinder 

 staining are obtained by this method. 



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



Mounting Old Museum Specimens as Microscopical Slides. § — 

 G. A. McKechnie says that satisfactory results may be obtained by the 

 following procedure : — 1. Soak the insect for a few days in solution of 

 carbonate of soda (j oz. to 10 oz. water). 2. Soak for a few days in 

 caustic soda (5 in. of stick to 2 oz. water). 3. Wash in water for many 



* Zeitschr. wiss. IMikrosk., xxviii. (1912) pp. 279-80. 

 i Zeitschr. wiss. ^Nlikrosk., xxviii. (1912) pp. 275-8. 

 X Zeitschr. wiss. Mikrosk., xxviii. (1912) pp. 417-24. 

 § Micrologist, i. (1912) pp. 116-7 



