1888.] MICKOSCOPICAL JOURNAL. 31 



stand for a short time, and, when the lime has partially settled, add a suffi- 

 cient quantity of a saturated solution of common washing soda to cause the 

 mixture to become thick and turbid. It is allowed to stand for several days, 

 and the clear supernatant liquid is then syphoned ofl'and preserved in a stop- 

 pered bottle, which should be kept in a dark place. This fluid bleaches 

 rapidly, usually in from 15 to 30 minutes; and care should be taken not to 

 submit sections to too prolonged action, as, being to a certain extent a solvent 

 of cellulose, the sections would be disintegrated and destroyed. 



Mayer's cochineal tincture. 



Cochineal, i gramme, 

 Alcohol (70%) 10 cc. 

 Rub up the cochineal in a mortar and mix it with the alcohol ; in five days 

 the clear fluid is poured off, and is filtered before being used. This stain, 

 which in its action is similar to Kleinenberg's hEematoxylin, is useful where a 

 higher degree of penetration is required than that possessed by the ordinary 

 aqueous solutions of cai'mine or cochineal. I have found it very useful for 

 brain and spinal cord, and for scirrhus and carcinoma of the breast. 



Klein's cochineal fluid.* 



' One per cent, of alum and cochineal in distilled water are boiled to four- 

 sevenths of the original volume ; when cool, a few drops of carbolic acid are 

 added, and the liquid filtered. Sections willstain well in three or four hours, 

 but will not be injured if left twenty-four hours. They require nothing but 

 washing in distilled water. The branching process of Purkinge's cells in the 

 cerebellum, the connection of the kite-shaped cells of the cerebral cortex, and 

 the "chief" and "investing" cells of the gastric mucous membrane are 

 rendered especially evident by this method.' 



NEW METHODS OF PREPARING CARMINE STAINING FLUIDS. f 



' Sig. G. Arcangeli states that the unsatisfactory results, and the instability 

 of the ordinary carmine stains, induced liim to try other methods, and he has 

 obtained excellent results by the following modifications : — 



' I. Boil together 100 grammes distilled water, 4 grammes boric acid, and 

 50 centigrammes carmine for about 10 minutes ; filter when tepid. The fluid 

 gives a beautiful cochineal-red stain, much resembling that of eosin. The 

 nuclei of vegetable tissues attain their maximum of coloration in about twenty- 

 four hours. The cutaneous epithelium and muscular fibres oi Ratia esculenta 

 stain well. It is necessary to be aware that the sections should not be washed 

 more than twice or three times in water, and should then be transferred to 

 alcohol, which seems to set the stain. | 



' 2. Another carmine stain, which gave the best results, was obtained by 

 boiling for about 10 minutes 100 cc. of a saturated solution of alum, 3 grammes 

 of boric acid, and 35 centigrammes of carmine. The fluid so obtained is of 

 a fine violet-red color, and stains the nuclei of animal and vegetable tissues in 

 about twenty-four hours ; and according as the sections are placed in an alco- 

 holic or aqueous solution of the stain, so is the greater or less rapidity of its 

 action. When used in an alcoholic solution, the stain is rapid, and the whole 

 of the cell participates in the process. When in combination with water only, 

 the action is slower and the nucleus alone is affected. 



'3. A third stain was made by substituting salicylic for boric acid. 100 

 grammes of a saturated solution of alum, 35 centigrammes of carmine, and 



* Journal of the Royal Microscopical Society, for 1881, p. 957. 



•f Journal of the Royal Microscopical Society, for 1885, p. 1095. 



X Alcohol fixes a carmine stain by precipitating the pigment. — A. J. D. 



