496 CHAPTER XXXIV. 



ripen for some days exposed to the air, or (Journ., 1895, 

 pp. 129, 248) adds to it a few drops of hydrogen peroxide, 

 until it becomes red-brown, when it is shaken up and filtered 

 on to the cover-glass and allowed to act for a minute. The 

 cover-glass is then mopped up and dried, and stained with 

 carbol-gentian. 



VAX ERMENGEM (Journ. 1894, p. 405) fixes for a few minutes 

 with a mixture of 1 part 2 per cent, osmic acid, and 2 parts 

 10 to 25 per cent, solution of tannin, washes, treats with 0'25 

 to 0'5 per cent, solution of nitrate of silver, then for a few 

 seconds with a mixture of 5 parts gallic acid, 3 of tannin, 10 

 of acetate of soda, and 330 of water, then puts back again 

 into the silver for a short time, then washes and mounts. 



See also the modifications of this method by STEPHENS, ibid., 

 1898, p. 685, and Gordon, ibid., 1899, p. 235, and the 

 methods of TRENKMANN (Centralbl., vi, 1889, p. 433; Zeit. f. 

 /rt'.y.s. Mik., vii, 1, 1890, p. 79) ; BROWN (Journ. Roy. Mic. 

 Soc., 1893, p. 268) ; JULIEN (ibid., 1894, p. 403) ; SCLAVO (Zeit. 

 f. u-iss. Mik., xiii, 1896, p. 96) ; HESSERT (ibid., p. 96) ; MUIR 

 (Journ. Roy. Mic. Soc., 1899, p. 235) ; McCRORiE (ibid., 1897, 

 p. 251 ; he stains for two minutes in a mixture of equal parts 

 of concentrated solution of night-blue, 10 per cent, solution 

 of alum, and 10 per cent, solution of tannic acid) ; ZETTNOW 

 (ibid., 1899, pp. 662, 664) ; MORTON (ibid., 1900, p. 131) ; 

 WELCKE (ibid., p. 132). 



