26 MANUAL OF HISTOLOGY. 



of silver, and, half an hour afterward, immerses it in water 

 acidulated with acetic acid ; after a day or two it is found to 

 have a glutinous appearance. The lamellae are then easily 

 stripped off, and in the middle portions, the corneal corpuscles 

 assume a purplish-brown color while their nuclei are uncol- 

 ored. The outlines of the lymphatic channels are also sharply 

 defined . 



Picro-hcematoxylin and eosine (triple-staining). Wendt 

 has described a method of double-staining by picric acid and 

 hsematoxylin. Only the very thinnest sections, however, give 

 satisfactory results. A strong solution of hsematoxylin is first 

 employed. In this the sections are allowed to remain about 

 twelve hours. After washing them in water, they are placed 

 in a saturated solution of picric acid and carefully watched. 

 They may be removed from time to time, examined with a low 

 power, and, when properly stained, put in alcohol and mount- 

 ed in Canada balsam with as little delay as possible. To ob- 

 tain triple- staining, eosine may be conveniently combined with 

 this picro-hsematoxylin method. To insure good results some 

 amount of practice is necessary. 



Double, triple, and quadruple staining. Dr. Gibbes re- 

 commends for double-staining, immersion first in picro-carmine 

 and then in logwood, or which is better, immersion first in a 

 spirituous solution of rosine or aniline violet, and then in an 

 aqueous solution of aniline blue or iodine green. In obtaining 

 more than two colors there is considerable difficulty. To ac- 

 complish it he uses first the chloride of gold or picro-carmine 

 and then the spirituous and aqueous solutions of the ani- 

 lines. 



Staining with BismarJc brown. Make a watery solution of 

 gr. ij. 3J-, heat and filter; soak in the solution about three 

 minutes ; set the color with acetic acid (glacial) 4 per cent, 

 for half a minute. After dehydrating with alcohol mount in 

 dammar varnish. Weigert prepares the Bismark brown as 

 follows : he makes a concentrated aqueous solution by boil- 

 ing in water, filtering from time to time. He also uses a weak 

 alcoholic solution, and combines with other colors. 



[To combine with eosine put the sections in a strong aqueous solution of 

 Bismark brown ; remove after about two minutes, set in weak acetic acid (four 

 per cent.), then place in a weak alcoholic or aqueous solution of eosine, and 

 then again in the acetic acid solution. T. E. S.] 



