84 CARMINE STAINS. 



(very elaborate, and has not afforded me a soluble carmine). FOL, Lehrb. d. 

 vergl. mic. Anat., p. 195. RUTHERFORD, Pract. Hist., p. 173. PAUL 

 MAYER, Mitth. Zool. Stat. Neapel, ii, p. 20. BASER, Mon. Micro. Journ., 

 xii, p. 48. PERGENS, Carney's Biologie Cellulaire, p. 92. HOYER, see 

 above, 141. BIZZOZERO, Zeit.f. wiss. Mik., 1885, p. 539. KLEMENSIEWICS, 

 Sitzb. Acad. Wiss. Wien, Ixxviii, 1878, iii, Juni ; Zeit.f. wiss. Mik., i, 1884, 

 p. 501. (Eub up 1 grm. of carmine with 30 of ammonia, and add 200 of 

 water. To the solution add half a vol. of saturated solution of picric acid ; 

 boil for 8 to 10 hours on a water bath, making up at first for evaporation by 

 adding dilute ammonia solution ; later, evaporate one half or two thirds. 

 On cooling, hardly any precipitate is formed. The solution is clear, very 

 dark red.) CUCCATI, Zeit.f. wiss. Mik., vi, 1, 1889, p. 42. 



148. Soda Picro-Carmine (Picro-carminate of Soda.) Soda 

 picro-carmine is not infrequently referred to as giving better 

 results than ammonia picro-carmine. The methods of prepara- 

 tion do not seem to have received due publication, and it is 

 not easy to meet with a formula. Here is one, due to LOWEN- 

 THAL (Anal. Anz., ii, 1887, No. 1, p. 22). Dissolve 1 grm. 

 of caustic soda in 100 grms. of water, add 0'4 grm. of carmine 

 and dissolve it by the aid of heat or by allowing it to stand for 

 twenty-four hours or more. Filter, and add 100 c. c. of water. 

 Then add gradually 20 to 25 c. c. of 1 per cent, picric acid 

 solution. This produces at first a precipitate that redissolves, 

 later a slight persistent precipitate. Add a few c. c. of the 

 picric acid in excess, let the solution stand an hour, and filter 

 (if necessary, two or three times through the same filter). 

 The filtrate may be concentrated by evaporation if desired. 



The ' Magazine of Pharmacy ' gives a formula similar to 

 the foregoing, except that the proportion of soda is reduced 

 to 0*05 per cent, (see Journ. Roy. Mic. Soc., 1888, p. 518). 



149. Alum-Carmine (GRENACHER'S formula, Arch. mik. Anat., 

 xvi, 1879, p. 465). An aqueous solution (of 1 to 5 per cent, 

 strength, or any other strength that may be preferred) of com- 

 mon or ammonia alum, is boiled for ten or twenty minutes 

 with 4 to 1 per cent, of powdered carmine. (It is perhaps 

 the safer plan to take the alum solution highly concentrated 

 in the first instance, and after boiling the carmine in it, dilute 

 to the desired strength.) When cool filter. 



This stain must be avoided in the case of calcareous struc- 

 tures that it is wished to preserve. 



TIZZONI (Bull. Sc. Med. Bologna, 1884, p. 259) and PISENTI 

 (Oazz. degli Ospetalt, No. 24; Zeit. f. wiss. Mik., ii, 1885 p. 



