STAINS FOB PLASMA CELLS. 417 



night. Dehydrate rapidly in absolute alcohol, differentiate 

 in creosol (details not given), rinse in xylol, and mount in 

 balsam. 



B. General Stain, also bringing out Plasma Cells. 

 Methylen blue . . . . . 1-Q 

 Carbonate of potash . . . . 10 



Distilled water 10OO 



Alcohol . . . . . 20' 



Heat on a water-bath until reduced to lOO'O. Use for 

 staining undiluted, or diluted with one vol. of anilin water. 

 Differentiate (details not given) with glycol, styron, or 

 creosol. Mastzellen are not differentiated. 



c. Stain giving Red Mastzellen with Blue Plasma Cells. 

 Methylen blue . . . . 1/0 



Kali Carbon, (natron carbon, ammon. 



carbon) ...... I'O 



Aq. dest. (Aq. carbolisata, chloroforma) 100*0 

 Dilute about 100-fold, stain slowly, treat with 70 to 80 per 

 cent, alcohol, differentiate in styron, and bring through 

 bergamot oil or xylol into balsam. In this process the 

 granules of the Mastzellen stain red in consequence of the 

 formation of methylen red in the staining bath. 



In a paper " Ueber Plasmazellen, insbesondere bei Lupus " 

 (for which see Monatschr. f. prakt. Dermatol., xii, 1891, p. 296, 

 or Zeit. f. wiss. Mik., ix, 1, 1892, p. 92), UNNA gives some 

 directions concerning the process of differentiation with 

 creosol. Creosol only differentiates the stain, it does not 

 dehydrate the sections. Sections should, therefore, first be 

 dried with blotting-paper, and should then be treated with 

 absolute alcohol for a few seconds, or with anilin oil before 

 applying the creosol. The time required for differentiation 

 in the creosol is from a few minutes to a few hours. When 

 the proper stage of differentiation is attained, it should be 

 fixed with xylol and the sections mounted. The method 

 shows Mastzellen of a cherry- red tone. 



' In a paper, 1. c. : xiii, 1891, p. 364 (see Zeit. f. wiss. Mik., xi, 1, 1892, 

 p. 89), VAN DEE SPEK and UNNA describe some further experiments. Main- 

 taining the method of staining given above under A, they find that besides 

 the differentiating agents given under B, a lengthy series of other reagents 



27 



