STAINING THE SECTIONS. 191 



Staining with dahlia and decolorizing with sodium ca.r- 

 bonate solution. Another method that is not very com- 

 monly employed, though the results obtained by its use 

 are in many cases very satisfactory, is to stain the tis- 

 sues in a strong watery solution of dahlia (about one- 

 fourth saturated) for from ten to fifteen minutes ; from 

 tliis they are transferred to a 2 per cent, solution of 

 sodium or potassium carbonate, and from this into alco- 

 hol, alternating from the one to the other until the 

 sections are almost colorless. After the alcohol they 

 are rinsed in water and then put into a dilute watery 

 solution of either eosin, Bismarck-brown, or safranin for 

 one minute, then washed out in alcohol, finally in abso- 

 lute alcohol, and then in xylol, from which they may be 

 mounted in the manner given. 



Especially brilliant results are obtained when tissues 

 containing anthrax bacilli are stained by this process ; 

 the bacilli will be of a deep-blue color, while the sur- 

 rounding tissues will be of the color used as contrast. 



Kuhne's carbolio methylene-blue method. Stain the 



sections in the following solution for from one-half to 



one hour : 



Methylene-blue, in substance . . . 1.5 grammes. 



Absolute alcohol . . 10 c.c. 



Rub up thoroughly in a mortar, and when the blue 

 is completely dissolved add gradually 100 c.c. of a 5 

 per cent, solution of carbolic acid. (This solution de- 

 composes after a short time ; it should be made fresh 

 Avhen needed.) From this the sections are washed in 

 water, then in 1.5 to 2 per cent, hydrochloric acid in 

 water, after which they are transferred to a solution of 

 lithium carbonate of the strength of six to eight drops 

 of a concentrated watery solution of the salt to ten drops 



