UNNA'S ORCEIN METHOD. 



stained of an intense black, the rest of the preparation show- 

 ing the usual characters of a safranin stain. 



The staining will be performed quicker if it be done at the temperature 

 of an incubating stove (GEIESBACH, ibid., iv, 1887, p. 442). And FEEBIA 

 (ibid., v, 3, 1888, p. 342) says that clearer preparations will be obtained if 

 the sections be left for a long time, say twenty-four hours, in the alcohol, or 

 be treated for a short time with very dilute alcoholic solution of caustic 

 potash. This decolourises more completely the ground of the preparations. 



Another safranin method, which seems to have the fault of requiring a 

 too minute attention to details, is that of MIBELLT, see Mon. zool. italiano, 

 1, p. 17, or Zeit.f. wiss. Mik., vii, 2, 1890, p. 225 (the report mJourn. Roy. 

 Mic. Soc., 1890, p. 803, is vitiated by a misprint). 



UNNA'S Orcein Method (Monatschr. f. prakt. DermatoL, xii, 

 1891, p. 394; Zeit.f. iviss. Mik., ix, 1, p. 94) is as follows : 

 Dissolve O'l grm. of Griibler's orcein in 20 grms. of 95 per 

 cent, alcohol and 5 grms. of water, and O'l grm. of concen- 

 trated hydrochloric acid in a like mixture of alcohol and water. 

 Take six to ten watch-glasses, and pour into each 10 drops of 

 the stain. Acidify them with the acid mixture, beginning with 

 5 or 10 drops for the first glass and increasing in the proportion 

 of 1 drop for each glass in succession. Put one or two sections 

 into each watch-glass and stain for twelve hours. Examine in 

 a drop of glycerin and choose the successful sections ; they 

 should show the elastic fibres of a saturated shiny brown on a 

 lighter ground. Counter-stain nuclei if desired. 



See also ZENTHOEFER, in Unna's DermatoL Studien, 1892, 

 or Zeit.f. wiss. Mik., ix, 4, 1893, p. 509. 



KOPPEN (Zeit. f. wiss. Mik., vi, 4, 1889, p. 473; and vi, 1, 

 1890, p. 22) gives the following : Stain sections of alcohol 

 material for fifteen to twenty-four hours in a freshly prepared 

 mixture of five parts concentrated solution of crystal- violet 

 ("Kry stall violett"), and 105 parts of 5 per cent, aqueous 

 solution of carbolic acid. Treat for two minutes with the 

 usual solution of iodine in iodide of potassium, then for five 

 minutes with 10 percent, salt solution, and for fifteen seconds 

 with 1 per cent, hydrochloric acid, Wash out in absolute 

 alcohol, clear with terebene followed by xylol, and mount in 

 balsam. Elastic fibres dark violet, stratum corneum of 

 cutis and sheath of Henle of hairs being also stained. 



BURCI (see Journ. Roy. Mic. Soc., 1891, p. 831; and 1892, 

 p. 292) stains sections for a minute or two in saturated alco- 



