METHYL VIOLET. 69 



stains yet known. It is the classical nucle'in stain for fresh 

 tissues. 



106. Bismarck Brown (Manchester Brown, Phenylen Brown, 

 Vesuvin, La Phe'nicienne) . A fairly pure nuclear stain that 

 will work either with fresh tissues or with such as have been 

 hardened in chromic acid. 



The colour is not very easily soluble in water. You may 

 boil it in water, and filter after a day or two (WEIGERT, in 

 Arch. f. mile. Anat., xv, 1878, p. 258). You may add a little 

 acetic or osmic acid to the solution. MAYSEL (Ibid., xviii, 

 1880, pp. 237, 250) dissolves the colour in acetic acid (this 

 solution does not give a permanent stain). Alcoholic solu- 

 tions may also be used. Paul Mayer recommends a saturated 

 solution in 70 per cent, alcohol; or Calberla's mixture ( 385), 

 or dilute glycerine (say of 40 per cent, to 50 per cent.) may 

 very advantageously be employed. 



The watery solutions must be frequently filtered. The 

 addition to them of carbolic acid has lately been recommended, 

 vide Journ. Roy. Mic. Soc., 1886, p. 908. Bismarck brown 

 stains rapidly, but never over stains. The stain is permanent 

 both in balsam and in glycerin. 



As has been noted above ( 93), Bismarck brown has the 

 property of staining certain cellular elements during life (for 

 this purpose it is necessary to see that the colour employed 

 be pure and neutral). 



107. Methyl Violet (Methylanilin = anilin- violet = Paris violet = in- 

 chiostro di Leonard!). The following process has been recommended by 

 Orth (Amer. Mon. Micr. Journ., i, 1880, p. 143 ; Journ. Roy. Mic. Soc., 

 N.S., i, 1881, p. 137) : Sections are to be soaked in water, and then brought 

 into the following solution : 



Anilin violet 1 part. 



Acetic acid .... . 300 parts. 



Mount, without washing out, but simply draining, in acetate of potash' 

 (acetate 2 parts, water 1 part). 



The stain will probably fade within a year or two. 



This process does not appear to be of more than very limited applicability. 

 The following, however, due to GEASEE (Deutsche Zeit. f. Chirurgie, xxvii, 

 1888, p. 538584 ; Zeit. f. wiss. Mik., v. 3, 1888, p. 378) may be very 

 generally useful. 



Sections are stained for from twelve to twenty-four hours in a (presum- 

 ably aqueous) solution so dilute that at the end of that time the sections 

 will have taken up all the colour from the liquid. They are then washed 



