184 NUCLEAR STAINS, COAL TAR 



also stain mucin, the ground-substance of connective tissues 

 (especially cartilage), the bodies of Nissl in nerve-cells, and the 

 yolk of ova. 



370. Henneguy's Permanganate Method (Journ. de VAnat. et de la 

 Physiol., xxvii, 1891, p. 397). Sections are treated for five minutes with 

 1 per cent, solution of permanganate of potassium. They are then 

 washed with water and stained (for about half the time that would have 

 been taken if they had not been mordanted with the permanganate) in 

 safranin, rubin, gentian violet, vesuvin, or the like, and are differentiated 

 with alcohol, followed by clove oil in the usual way. 



The mordanting action of the permanganate is so energetic that if it 

 has been overmuch prolonged before staining with safranin, or, still 

 more, with rubin, it becomes almost impossible to differentiate the 

 sections properly ; it may be necessary to leave them for a month or 

 more in clove oil. 



371. Ohlmacher's Formaldehyde Process {Medical News, February 

 16th, 1895). Ohlmacher states that formaldehyde is a powerful 

 mordant for tar colours. Tissues may either be mordanted separately 

 by treatment for a short time (one minute is enough for cover-glass 

 preparations) with a 2 per cent, to 4 per cent, formalin solution ; or the 

 formalin may be combined with the stain. One grm. of fuchsin or 

 methylen blue dissolved in 10 c.c. of absolute alcohol may be added to 

 100 c.c. of 4 per cent, formalin solution. Sections are said to stain in 

 half a minute and to resist alcohol much more than is the case with 

 those treated by the usual solutions. 



372. Safranin. One of the most important of these stains, on 

 account of its power, brilliancy, and permanence in balsam, and 

 the divers degrees of electivity that it displays for the nuclei and 

 other constituent elements of different tissues. Solubility at 

 26° C. : in water 5-45 per cent., in alcohol 3-41 per cent. 



The great secret of staining with safranin is to get a good safranin. 

 In ordering it is well to specify whether you want it for staining 

 muclei or for staining elastic fibres, or for what other purpose you 

 may require it. There are presumably at least a score of sorts 

 of safranin on the market, differing to a considerable extent in 

 colour, weight, solubility, and histological action. Some are 

 easily soluble in water and not so in alcohol, some the reverse, 

 and some freely soluble in both. The brand Lee had been using 

 for a long time, which gave good results, was the " Safranin O " 

 of Grubler & Co. 



Conn (op. cit.) writes: " Grubler «fc Co. sell four types of safranin ; 

 safranin pur, safranin gelb, safranin O wasserloslich, and safranin sprit- 

 loslich. The first of these is apparently methylen violet, the others are 

 Safranin O." 



Staining. The majority of safranins are not sufficiently soluble 

 in water, so that solutions in other menstrua must be employed. 



Pfitzner {Morph. Jahrb., vi, p. 478, and vii, p. 291) advised 

 a solution of safranin 1 part, absolute alcohol 100 parts, and 

 water 200 parts, the last to be added only after a few days. 



