METHODS OF SPECIAL STAINING ETC. G61 



violet. Material dehydrated and imbedded in the usual way is 

 unsatisfactory. Intra-vitam staining is also unpromising. 



Craft's method {Stain Tech., vi, 1931, p. 127). Cut free-hand 

 sections from fresh material and place them in a solution of 

 0-75 grm. KI and 0-5 grm. iodine in 100 c.c. water for five minutes. 

 Swell five minutes with 10 per cent, sulphuric acid. Then mordant 

 five minutes in a solution of 1 grm. iodine and 1-25 grm. KI m 

 100 c.c. of 5 per cent, sulphuric acid. Wash in 5 per cent, sulphuric 

 acid until the iodine starts to fade, changing the liquid once or 

 twice. Transfer to freshly mixed stain (0-5 per cent, aqueous 

 gentian violet in 5 per cent, sulphuric acid, made up to form a 

 dark green solution). Heat to about 50° C. and allow to stand five 

 minutes. Wash sections quickly in 5 per cent, sulphuric acid. 

 Intensify the stain and clear the cell walls by immersion in a weak 

 solution of iodine-potassium iodide in 5 per cent, sulphuric acid 

 for one to two minutes. Mount in a mixture of 30 c.c. glycerin, 

 2 grm. zinc chloride and 0-1 grm. iodine and a bit of KI in 60 c.c. 

 water. Eventually the stain crystallises out ; keep the preparation 

 cool to retain it longer. See also Livingston, Amer. J. Bot., 

 xxii, 1935, p. 75. 



1326. Spermatozoids, zoospores, motile gametes and other 

 motile naked bodies are best fixed as a suspension in a drop of water 

 (or culture medium) with the vapour from a 1 per cent, osmic 

 acid solution (Steil, BoL Gaz., Ixv, 1918, p. 562). Dry the slide 

 and stain. A variety of stains may be used. Steil stains in 

 safranin ten minutes to one hour, then washes in water and in 

 95 per cent, alcohol until only the nucleus remains stained. If 

 necessary, next clear in xylol and remove the xylol with 95 per 

 cent, and absolute alcohol. Then stain in acid fuchsin ten to 

 twenty seconds, wash in absolute alcohol, clear in clove oil and 

 xylol and mount in balsam. Nucleus bright red, cytoplasm a 

 bluish-pink. He also obtained good results by staining in iron 

 htematoxylin. Iodine green and acid fuchsin, Delafield's hsema- 

 toxylin, Flemming's triple and others may also be used. 



s'howalter {Ann. BoL, xl, 1926, p. 702) considers Heidenhain's 

 hsematoxylin best for details of Bryophyte antherozoids. He 

 recommends Bismark brown as a counterstain to show the 

 gelatinous envelope. For the general form, and some details, 

 stain in dilute gentian violet, rinse in water, dry, and add a drop 

 of balsam and a coverslip. 



For Cotner's method for fungal zoospores see § 1399. 

 Cilia. To observe, mount organisms in a dilute solution of 

 cocaine. They may be observed in motion by the method of 

 Biitschli ( Ueber de Bau der Backterien und verwandter Organismen, 

 Leipzig, 1890). He suspends fine granules of carmine in the fluid 

 containing the organisms. 



MiGULA {Bot. Centrbl, xliv, 1890, p. 72) adds a very small 



