CARMINE AND ANILIN BLUE. 123 



I find the method gives admirable results when applied far 

 sections, but very bad results if it be attempted to stain in the 

 mass with the indigo. The indigo over-stains the superficial 

 layers before it has penetrated to the deeper layers. 



230. Merkel's Carmine and Indigo-Carmine in one Stain (MEE- 

 KEL, Unters. a. d. anat. Anst. Rostock, 1874 ; Month. Mic. Journ., 1877, 

 pp. 242 and 317). 



(A) Take 2 gr. of carmine ; 8 gr. of borax ; and 128 c.c. of water (or, 

 half a drachm of carmine, two drachms of borax, and four ounces of water). 

 Eub up in a mortar, allow the fluid to stand some time, decant, filter, and 

 keep in a stoppered bottle. 



(B) Take 8 gr. of indigo-carmine ; 8 gr. of borax ; and 128 c.c. of water 

 (or, two drachms indigo-carmine, two drachms borax, and four ounces water). 

 Mix, decant, filter, and preserve, as before. 



Before using, mix A and B in equal proportions. 



The objects to be stained must be thin ; all traces of chromic acid or 

 chromates must have been carefully washed out from them ; and they must be 

 soaked in alcohol before staining. Stain for fifteen or twenty minutes (MAX 

 FLESCH finds it better to stain for several hours, see Zeit. f. wiss. Mik., 1885, 

 p. 350). Wash out with saturated aqueous solution of oxalic acid, for a 

 rather shorter time ; wash the acid out with water, and mount as desired. 



The oxalic acid is necessary for fixing the indigo-carmine, which, being 

 very soluble in water, would otherwise be washed out- Unfortunately, it 

 precipitates carmine, so that successful preparations are not easily obtained , 

 the carmine being generally either precipitated or turned into a straw colour. 



Authors (MEEKEL, loc. cit.; NOBNIS and SHAKESPEABE, Amer. Journ. 

 Med. Sc., January 1877 ; MEEKEL, Mon. Mic. Journ., 1877, p. 242 ; MAESH, 

 Section Cutting, p. 85 ; 1&YKXL,Arch.f. mik. Anat., xxiii, 1885, p. 36 37) 

 are unanimous in stating that successful preparations show a most richly 

 differentiated and yet very precise colouring. According to Bayerl, the 

 stain is quite specifically elective for red blood-corpuscles, which are stained 

 of an apple green. The ground substance of cartilage and bone stains blue, 

 their cells red. 



The stain is not perfectly permanent. Bayerl recommends that benzin be 

 used for clearing, in lieu of clove oil, which oxydises the stain and injures it. 



This method has recently been recommended for Nerve Centres. For 

 Bayerl's application of it to ossifying cartilage (see Part II). 



I have put this method in small type, because though admirable for certain 

 special purposes, it is not at all to be recommended for general work. 



231. Carmine and Anilin Blue (or Bleu Lumiere, or Bleu de 

 Lyon). DUVAL (Precis de technique microscopique, 1878, p. 225) 

 proceeds as follows : Stain with carmine " in the ordinary 

 way;" dehydrate; and stain for a few minutes (ten minutes 

 for a section of nerve-centres) in an alcoholic solution of 

 anilin blue (ten drops of saturated solution of anilin blue 



