ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 899 



New Method of Double-staining.* — Dr. A. Garbini uses two differ- 

 ent solutions : — (1) Watery solution of anilin blue, 1 grin. ; aq. dest., 100 

 c.cm. ; abs. alcohol, 1-2 c.cm. (2) Safranin, ■ 5 grm. ; dist. water, 

 100 c.cm. ; abs. alcohol, 50 c.cm. The sections, either free or fixed by 

 Mayer's method to the slide, are immersed from one to four minutes 

 in the first solution, then washed in water, and then laid in a 1 per 

 cent, solution of ammonia until almost all the colour has disappeared. 

 The sections are next placed for five to ten minutes in a • 5 per cent, 

 solution of hydrochloric acid, are then again washed in a large quan- 

 tity of water, and are finally placed for four or five minutes in the 

 second solution, from which they are transferred directly to absolute 

 alcohol. Here the sections lose their violet colour to assume a sap- 

 phire blue hue. They are then passed through oil of cloves, xylol, 

 and mounted in xylol balsam. 



According to the author this method offers the following advan- 

 tages : — It may be used for any animal or vegetable tissue, imparting 

 to the individual elements their characteristic staining, and even to 

 the different cells of an organ (delomorphous and adelomorphous 

 cells, salivary and mucous cells), the protoplasm staining in various 

 colours. 



Merkel's Double Stain with Indigo and Carmine.f — For this 

 safe and excellent stain Dr. M. Flesch uses material hardened in 

 chromic acid or Midler's fluid, followed by immersion in alcohol. 

 The alcohol treatment is proceeded with without previous washing 

 in the dark ; much time is thereby saved, and the preparation in no 

 way loses any staining susceptibility. This procedure is especially 

 recommended for nervous tissue, as the brown coloration, which is 

 regarded by Weigert as indispensable for the success of his stain, 

 never fails. The alcohol can be filtered and used over again, so that 

 the cost is not very great. The author has usually experimented on 

 objects imbedded in celloidin, but paraffin preparations previously 

 saturated with turpentine or chloroform take on the stain. Unfor- 

 tunately the celloidin is stained along with the preparation ; the 

 colour, however, with great care and prolonged washing gradually 

 becomes so pale, that this disadvantage need scarcely be considered. 



The dye is a mixture of the solutions of carmine (carmine 2, 

 borax 8, H 2 130) and indigo carmine (indigo-carmine' and borax 

 each 8, water 130) in equal parts. This mixture can be kept for a 

 week : if kept longer, a precipitate forms, and the carmine acquires 

 the disadvantage of staining too deeply. 



The staining requires a much longer time than Bayerl stated. 

 Textures should be left at least twenty-four hours in the solution at 

 ordinary temperatures ; one to two hours in an incubator. The author 

 much prefers the former. After staining, the superfluous pigment is 

 extracted by immersion for half an hour in a saturated solution of 

 oxalic acid. It is always possible to render the water more blue or 

 more red, according as the staining or extraction time are varied. 



* Zool. Anzeig, ix. (1SSG) pp. 2G-9. 



t Zeitschr. f. Wiss. Mikr., ii. (1885) pp. 349 52 



3 N 2 



