214 



THE AMERICAN MONTHLY 



November, 



furnishes beautiful though pale prepa- 

 rations. Osmic acid did not do so 

 well as chromic, the latter preferred. 

 The sections are carefully washed in 

 water, then laid in the dye as safranin 

 12-24 hours, then in equal parts alco- 

 hol and water. Then washed and put 

 into white boxes with absolute alcohol 

 for half a minute till transparent, 

 then into clove oil, cleared up and 

 mounted in dammar, in which they 

 are permanent. 



112. Pfitzner. Ueber den feineren 



Bau der bei der Zelltheilung 

 a u f t r e t e n d e n fadenformigen 

 Dift'erenzirungen des Zell- 

 kerns. Morphoi. Jahrbuch. 

 vii, 289. 

 Having repeated many of the ex- 

 ])eriments with safranin described in 

 former numbers of the Jahrbuch, 

 Pfitzner condemns them all, and as- 

 serts that no commercial safranin 

 stains a nucleus well. He employed 

 a good dye from Friedrich Schafer in 

 Darmstadt. 



(A good safranin as well as most 

 of the anilin dyes may now be bought 

 at various places, as from Dr. Georg 

 Grubler, Leipzig, Dufour Strasse, 



17)- 



113. Ehrlich. Ueber das Methylen- 



blau und seine klinisch-bac- 



terioscopish Verwerthung. 



Zeitsch. f. klin Med., ji, 1881, 



p. 710. 

 Only basic dyes are suitable for in- 

 vestigations of bacteria. Those com- 

 monly used, like Bismarck brown, 

 fuchsin, methyl and gentiana violet 

 stain too deeply, some form granular 

 precipitates liable to cause errors. 

 Methyl blue appears to be free from 

 these objections. A solution in water 

 is used, and the dried preparation, 

 soaked for a suitable time, i to 24 

 hours, then washed, dried, and 

 mounted in Canada balsam. The 

 blue used is from Hesterburg, Berlin, 

 Louisenstrasse, 39. 



114. Griesbach. Ein neues Tinc- 



tious-mittel fur menschliche 

 und thierische Gewebe. Zool. 

 Anz.. 1882, p. 406. 



Iodine green proves to be a supe- 

 rior dye, and in many respects sur- 

 passes any of the anilins heretofore 

 used in microscopy. It does not ap- 

 pear to have been before applied, and 

 is preferred in a water solution of i 

 part to 35, though it does very well 

 in alcohol. Staining is instantaneous, 

 and the mounts may be in balsam. 

 Unfortunately, iodine green is no 

 longer manufactured, because too 

 costly, and methyl green offers an in- 

 ferior substitute, which may be ap- 

 plied in a similar manner. 



115. Flesch. Kleine Mittheilungen 



zur histologischen Technik. 



Zool. Anz., 1882, p. 554. 

 The application of iodine green 

 and methyl green, supposed by Gries- 

 bach to be new, is shown to be old in 

 England, where it was recommended 

 for double staining. Combinations 

 of green and red anilins are recom- 

 mended. (I have mvself used iodine 

 green in 1881). 



116. Weigert. Ueber eine neue Un- 



tersuchungs-methode des Cen- 



tralnervensystems. Centralbl. 



f. d. med. Wiss., 1882, pp. 



753 and 772. 

 Acid fuchsin stains the central nerves 

 in a way hitherto unknown. Fuchsin 

 (of the Badische Anilin Soda Fabrik, 

 No. 130) is used in concentrated so- 

 lution. Also add i gramme of caustic 

 potash to 100 c. c. absolute alcohol in 

 a closed flask, allow it to stand 24 

 hours, filter, and mix 10 c, c. with 

 100 c. c. alcohol as solvent for the 

 dye. Alcohol saturated with salt is 

 used as a dehydrator. 



If nerve sections are merely treated 

 with acid fuchsin, the differentiation 

 is feeble, but if after staining they are 

 put in alkaline alcohol, and the dye 

 soaked out, the structure becomes 

 distinct because the grey matter 

 chiefly retains the color. The fol- 

 lowing is the exact process : — Sections 

 hardened in chrome salts are laid in 

 the dye for an hour, then in water 

 and washed, then in dilute alkaline 

 alcohol, in which they remain till the 

 gray substance Is distinctly seen. 



