146 CHAPTER XII. 



222. Iron Carmine (ZACHARIAS, Zool. Anz., 1894, p. 62). Stain for 

 saveral hours in an aceto-carmine (made by boiling 1 grin, of carmine 

 with 150 to 200 c.c. of acetic acid of 30 per cent., for twenty minutes, and 

 filtering). Rinse the objects with dilute acetic acid, and bring them 

 (taking care not to touch them with metallic instruments) into a 1 per 

 cent, solution of ammoiiiated citrate of iron. Leave them, for as much 

 as two or three hours if need be, till thoroughly penetrated and blackened 

 (with sections this happens in a few minutes). Wash for several hours 

 in distilled water. A chromatin and plasma stain. 



223. Iron Carmalum (DE GROOT, Zeit. wiss. Mill., xx, 1903, 

 p. 21). Dissolve O'l grm. of ferric alum in 20 c.c. distilled 

 * water and add 1 grm. carminic acid. Dissolve, add 180 c.c. 

 of water, warm, add 5 grms. potash alum, dissolve, cool, 

 filter, and add-2 drops of hydrochloric acid. To be used as 

 carmalum, and said to give a stronger strain. 



224. Iron Cochineal (SPULER, Encyclopaedic d. mik. Technik, 1903, 

 p. 153, and 1910, p. 240). Stain for 48 hours in a stove, in extract of 

 cochineal (made in a highly complicated way), wash with water, put 

 into solution of ferric alum of per cent, strength for 24 hours or 

 more. If the stain is not sufficiently intense, the whole process may be 

 repeated. 



PETER (Zeit. wiss. Mile., xxi, 1904, p. 314) stains material in bulk for 

 48 hours (sections 18 to 24) in an incubator, in a similar extract, acidi- 

 fied with HC1, treats with iron-alum of 2| per cent, for one hour to one 

 day (sections half to two minutes), then alcohol, xylol, paraffin, or 

 balsam. Chromatin black, protoplasm grey, yolk granules red. 



HANSEN (ibid., xxii, 1905, p. 85) stains sections or entire objects in a 

 solution of 5 to 10 grms. cochineal, 8 grms. ferric alum, 250 c.c. water, 

 and 25 c.c. sulphuric acid of 10 per cent., boiled for fifteen to twenty 

 minutes. 



/3. So-called " Neutral " and Alkaline. 



225. Ammonia- Car mine. Best made by the method of RANVIER. 

 Make a simple solution of carmine in water with a slight excess of 

 ammonia, and expose it to the air in a deep crystallising dish until it is 

 entirely dried up. It should be allowed to putrefy if possible. Dissolve 

 the dry deposit in pure water, and filter. 



VAN WIJHE (Vers. Akad., Amsterdam, viii, Deel, p. 507) takes an old 

 strong solution of carmine in ammonia (or boils carmine with ammonia 

 and peroxide of hydrogen), then precipitates it by adding alcohol to 

 excess, washes the precipitate with alcohol, and dries it. 



226. Soda-Carmine appears to be still used by some for central 

 nervous system (see CUCCATI, Zi.it. wiss. Mik., iv, 1887, p. 50). It can 

 be obtained from GRUBLER & HOLLBORN (Natron-Carmin), 



