ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 1091 



Gold Chloride for Sclerosis of Nervous Tissue.* — Dr. A. Wittig, 

 after hardening in Midler's fluid and in alcohol, transfers the spinal 

 cord to a 2 per cent, solution of gold chloride in alcohol of 47 per 

 cent., wherein the preparations remain from six to eight hours, and 

 are afterwards transferred to a 20 per cent, soda solution. After 

 three or four minutes they are removed from this fluid, drained on 

 blotting-paper, and thereupon are immersed in a 10 per cent, solution 

 of iodide of potassium. In this the sections remain 15-30-45 

 minutes, and are then washed in water. Clearing up is effected by 

 means of bergamot oil or turpentine-creosote and the preparations 

 are mounted in Canada balsam. In this manner were obtained 

 images in no way inferior to those from Weigert's hematoxylin. 

 The medullated nerve-fibres appear dark blue on a reddish ground ; 

 the ganglion cells, somewhat less darkly stained, showed clearly tho 

 nucleus, together with nucleoli, and numerous processes. 



Fixing and Staining Flagellata.f — Dr. J. Kiinstler did not use, in 

 his researches on Flagellata, alcohol and chromic acid, as these fluids 

 gave indifferent results (except in some special cases, e. g. trichocysts). 

 The best reagent is osmic acid in a very concentrated, form ; weak 

 solutions and the vapour are unsuitable. The author takes 1 grm. of 

 the pure acid and dissolves it in some cubic centimetres of water. 

 The fluid should have a citron-yellow colour. At the bottom of the 

 vessel is usually some undissolved osmic acid. A drop of the fluid 

 containing the Infusoria to be examined is placed on a slide, and then 

 a drop of the osmic acid solution immediately added. The animals 

 are thereby fixed at once. Before staining the acid is allowed to 

 evaporate to prevent over-blackening. A small drop of the staining 

 fluid (the author used metbylen green and a concentrated solution of 

 cyanin) is added to the fluid on the slide, a cover-glass imposed, and 

 then closed with paraffin and wax ; or the preparation may be left 

 for 24 hours in a moist chamber in contact with a drop of the stain. 

 Then dilute glycerin is added very sparingly, and the preparation 

 closed as before. 



The internal protoplasmic substance of the Flagellata is stained 

 and contracted, but the hyaline sheath remains to show the original 

 form of the animal. 



Double - staining Botanical Preparations. J — The following- 

 method " B.Sc." has found very successful in showing clear differentia- 

 tion, besides producing slides of great beauty (he is indebted to Prof. 

 Eothrock for the process). 



Immerse the section in a very, very ivcalc solution of anilin-green 

 for twenty-four hours (at the end of twelve hours the section will 

 most likely have absorbed all the green, in which case add two drops 

 more of the mother solution). Then take a middling strong solution 

 of Beale's carmine, and dip the section in it for from one to five 

 minutes only ; then prepare with alcohol and clove-oil in the usual 

 way, bedding in dammar, lac, or Canada balsam. 



* 34 pp., 8vo, Breslau, 1885. 



t Journ. do Microgr., x. (18S6) pp. 17-2">, 5S-G3 (1 pj.). 



J Scientif. Enquirer, i. (18SG) p. 33. 



4 b 2 



