ZOOLOaY AND BOTANY, MICROSCOPY, ETC. 557 



After tlie action o£ malachite-greeri many organisms die in a state 

 of extension ; in Vorticellas the contractile peduncle becomes inert, 

 and its central part coloured, before the vibratile cilia lose their 

 movements and the peristoma ceases to contract. 



By the simultaneous emj)Ioyment of dahlia and malachite-green 

 the nucleus can be stained green and the protoplasm violet. 



Diphenylamine-blue, which colours deeply vegetable debris, dead 

 organisms, and some living microbes, colours neither parenchyma, 

 nucleus, nor contractile vacuole of Infusoria, except the central part 

 of the contractile peduncle of Vorticellas. 



M. Certes has tried the cultivation of micro-organisms on plates 

 of jelly coloured by diphenylamine-blue. The development of the 

 colonies goes on in the usual way. Some remain uncoloured ; others, 

 apparently identical, are coloured. The jelly becomes decolorized 

 whenever it is liquefied by the organisms. 



Staining Vaucheria and Chara.* — Dr. J. Schaarschmidt finds 

 that the granules of Vaucheria (V. sessilis, and V. geminata) which 

 have been treated with osmic acid, glycerin, and alcohol, show 

 different reactions with stains and reagents to those of Saprolegnia. 

 The internal spongy part of the younger granules takes up the stain- 

 ing material with avidity, whereas the peripheral part remains 

 colourless or only faintly stained. 



They are most strongly stained by nigrosin, rosanilin, eosin, 

 and safiranin ; methyl-violet and gentian-violet stain especially the 

 inner part of the granules. They are very resistant to strong 

 chemicals, and in dilute or fairly concentrated sulphuric acid they are 

 hardly altered even after several days. They are only dissolved by 

 quite concentrated sulphuric acid. 



Staining of Koch's Bacillus. f — Dr. B. Frankel proposes the 

 following formula and methods : — 



3 c.cm. anilin oil are dissolved in 7 c.cm. alcohol (or 1*5 c.cm. 

 toluidin in 8 • 5 c.cm.) and added to 90 c.cm. of distilled water. To 

 100 parts of this 11 parts of a saturated watery solution of methyl- 

 violet or fuchsin (Weigert). To prepare a solution fresh for use 

 Frankel heats about 5 c.cm. of anilin or toluidin to boiling in a test- 

 tube, and pours it into a watch-glass. To this hot solution the 

 alcoholic solution of the dye is added drop by drop until a deep opales- 

 cent colour but no precipitate is obtained. Cover-glass specimens of 

 bacteria floated on this hot solution are stained in two minutes. 



The following solutions are used for contrast staining. 



1. Blue. Alcohol 50, water 30, nitric acid 20; as much methyl- 

 blue as is dissolved by shaking. 



2. Brown. Alcohol 70, nitric acid 80; as much vesuvin-brown 

 as will dissolve. 



3. Green. Alcohol 50, water 20, acetic acid 30 ; as much mala- 

 chite or methyl-green as will dissolve. 



The cover-glasses are stained in these solutions fur 1-2 minutes, 



* Mao;yar Novc'nytaui, viii. (188i") pp. 1-13. 

 t Berl. Klin. Wcchenscbr., 1884, No. 13. 



