OYTOLOGICAL METHODS. 329 



four weeks in bichromate of 3 per cent., and stains in 

 iron haematoxylin. 



Mitochondria are frequently found stained by many of 

 the current stains, iron haematoxylin in particular sometimes 

 staining them with a sharpness that is not attained by any 

 other method. These results are more or less accidental 

 and sporadic : but it is claimed for BEN DA'S alizarin method 

 that it gives a certain and specific stain of them, enabling 

 them to be distinguished from other morphologically similar 

 formations. 



BKNDA'S Alizarin Method (Ergebnisse der Anat., xii, 1902 

 (1903), p. 752, and other places) is as follows: Harden for 

 eight days in strong liquid of Flemining (the acetic acid 

 therein being reduced to three drops). Wash for an hour 

 in water and put for twenty-four hours into a mixture of equal 

 parts of pyroligneous acid and 1 per cent, chromic acid, then for 

 twenty-four hours into bichromate of potash of 2 per cent., 

 wash for twenty-four hours and imbed in paraffin. Sections 

 on the slide are mordanted for twenty-four hours with 4 per 

 cent, solution of ferric alum or diluted liq. ferri sulfur. 

 oxydat., then rinsed with water and put for twenty-four 

 hours into an amber-yellow aqueous solution of Kahlbaum's 

 sulf alizarin ate of soda, prepared by dropping 1 c.c. of 

 saturated alcoholic solution thereof into 80 to 100 c.c. of 

 water. Rinse in water, Hood the slides with the solution of 

 crystal violet 330, diluted with an equal vol. of water, and 

 warm till vapour is given off. Rinse, differentiate one or 

 two minutes in oO per cent, acetic acid (till the nuclei come 

 out reddish), wash in running water for five to ten minutes, 

 dry with blotting paper, dip into absolute alcohol, pass 

 through bergamot oil into xylol and balsam. Mitochondria 

 violet, chromatin and " archoplasm ' brown-red, certain 

 secretion granules pale violet, centrosomes red violet. 



Instead of the staining solution prescribed above (which 

 may be kept in stock) you may take (Encycl., ii, p. 198) a 

 freshly prepared mixture of equal parts of anil in water and 

 saturated alcoholic solution of crystal violet and this is to 

 be preferred. 



PRENANT (Jouni. de VAnat. ct Pliys., xlvi, 1910, p. 217) finds tlmt 

 methylen or toluidin blue, or other basic dyes, may he used instead of 

 the crystal violet. 



