388 BLOOD AND GLANDS. 



788. WEIGERT'S Fibrin Stain (Fortschr. d. Med., v, 1887, No. 8, 

 p. 228). Sections (alcohol material) are stained in a saturated 

 solution of gentian or methyl violet in anilin water ( 286). They 

 are brought on to a slide and mopped up with blotting-paper, and a 

 little Lugol's solution is poured on to them. After this has been 

 allowed to act for a sufficient time they are mopped up with blotting- 

 paper, and a drop of anilin is poured on to them. The anilin soon 

 becomes dark, and is then changed for fresh once or twice. The 

 anilin is then thoroughly removed by means of xylol, and a drop of 

 balsam and a cover are added. This stain may be applied to 

 celloidin sections without previous removal of the celloidin. 



See also the modifications of this method by KROMAYER ( 656) ; 

 BENECKE ( 690) ; UNNA (Monatssch. prakt. Dermal., xx, 1895, p. 140) ; 

 WOLFF (Zeit. iviss. Mile., xv, 1899, p. 310) ; and one of another sort by 

 KOCKEL (Centralb. allg. Path., x, 1899). 



789. Elective Staining of Erythrocytes (K. OKAJIMA, Anat. Record, 

 xi, 1917). This stain is based on the fact that the phosphomolybdic 

 acid lake of alizarin stains, shows a special affinity for haemoglobin. 

 Fix material in formol, sublimate, chrome, etc. Transfer sections 

 on slide to aq. dest. ; mordant in 10 per cent, phosphomolybdic 

 acid solution for thirty seconds to two minutes ; wash in water ; 

 stain in this mixture for twenty minutes to twenty hours : sodium 

 sulfalizarinate, saturated aqueous solution, 100 c.c. ; and 10 per 

 cent, phosphomolybdic acid, aq. solution, 30 c.c. (10 to 50 c.c.) ; 

 wash in water ; alcohols, xylol, balsam. Erythrocytes go bright 

 yellow orange. Counter-staining may be done in Ehrlich's hsema- 

 toxylin. 



The completeness of the " specificity " of this method is open to 

 doubt, but it gives interesting results. 



790. Intravital Staining with Benzidine Dyes. BOUFFARD (Ann. 

 de VInst. Pasteur, xx), then GOLDMANN (Beit. z. Klin. Chir., Ixiv, 

 have shown that animal tissues may be " stained " intra vitam by 

 the injection of several benzidine dyes. There are some categories 

 of cells in the body which seem to show a special affinity for phagocy- 

 tosing or, at least, ingesting in some way granules of certain of 

 these colloid dyes. These various cells are often called pyrrhol cells 

 (Goldmann), macrophages (Evans), histiocytes (Aschofi-Kiyono), 

 or resting wandering cells (Tschaschin). 



According to HAL DOWNEY (Anat. Record, xii, 1917) the process of 

 " staining " is one of storage or iugestion, and not of true staining, and 

 attempts to classify cells according to their reactions to these colloidal 



