HAMATEIN (HJ1MATOXYLIN) STAINS. 187 



(Mitth. a. (I Zool. Stat. zu Neapel x, 1, 1891, p. 174), and that of SQUIRE, 

 in his Methods and Formulae, p. 25, and the alternative formulae of SQUIRE 

 (loc. cit.) and of VON WISTINGHAUSEN (Mitth. Zool. Stat. Neapel, x, 1891, 

 p. 41 ; Zeit.f. wiss. Mik., x, 4, 1893, p. 479). 



249. BURCHARDT'S Pyroligneous Acid Hsematoxylin (Arcli.f. mik. 

 Anut., liii, 1898, p. 232; Zeit.f. wiss. Mik., xv, 4, 1899, p. 453; Journ. 

 Roy. Mic. Soc., 1899, p. 453) would seem to be superfluous at least. 



250. Other Alumina-haematein Solutions. A large number of 

 suppressed receipts will be found given in the earlier editions. 



B. Other Hsematein or Hsematoxylin Compounds. 



251. Introduction. There remain to be described the stains 

 derived from the compounds- of haematein or haematoxylin 

 with iron, copper, chrome, vanadium, and molybdenum. 

 Only those, however, of general applicability will be de- 

 scribed in this place ; those which are only employed as 

 specific stains for nervous tissue (Weigert-Pal, etc.) finding 

 their place under Neurological Methods. The iron stains can 

 only be employed for sections ; the chrome stains may also 

 be used on material in bulk. 



252. R. HEIDEXHAIN'S Chrome Heematoxylin (Arch. f. mik. Anat. y 

 xxiv, 1884, p. 468, and xxvii, 1886, p. 383). Stain for twelve to twenty- 

 four hours in a ^ per cent, solution of hsematoxylin in distilled water. 

 Soak the objects for the same length of time in a 0'5 per cent, solution of 

 neutral chromate of potash, which should be changed, if necessary, several 

 times. Wash out the excess of chromate with water. 



The above is a slightly modified form of the original process, in which 

 staining was done in a stronger haematoxylin solution (0'5 to 1 per cent.), 

 and bichromate was used for washing out instead of neutral chromate. The 

 more recent process gives a sharper chromatin stain. 



The stain succeeds best with alcohol or picric acid objects, but it will 

 succeed with chromic objects if they have been very well washed, or with 

 material fixed in Flemming's mixture. 



Objects that have been fixed in corrosive sublimate ought to be very care- 

 fully washed out with iodine, or the like (see 66), as neutral hsematoxylin 

 forms a black precipitate with any excess of sublimate that may remain in 

 the tissues (see TORNIER, in Arch.f. mik. Anat., 1886, p. 181). 



The stain is black to grey. It is a sharp stain, remarkably rich in detail. 

 It is a plasma-stain as well as a chromatin stain. 



The process is adapted to staining in bulk. You can decolour the objects 

 to any extent by prolonging the washing in the chromate. 



