214 SUMMARY OF CURRENT RESEARCHES RELATING TO 



is Ziehl's carbol fuchsin. On the unfixed film are poured one drop of 

 the mordant and four or five drops of the stain. The mixture is allowed 

 to act for 15, 20, or 25 minutes. The preparation is then washed, dried, 

 and mounted. 



Staining and Mounting Urinary Deposits.* — The editor of the 

 National Druggist gives the following outlines of the procedure he 

 has successfully adopted for some sixteen years for collecting, preserv- 

 ing, staining, and mounting tube - casts, epithelia, and other urinary 

 deposits. If the urine has to come from a considerable distance a 

 crystal of naphthalin should be placed in the bottle. This will pre- 

 serve it for several days from decomposition. When received, the urine 

 is placed in a cool place, e.g. a refrigerator, to settle. When the upper 

 two-thirds have become clear this portion is siphoued or decanted off. 

 A few drops of 2 p.c. osmic acid are then added, and afterwards sufficient 

 eosin solution to make the whole strongly red. The urine glass is now 

 exposed to a strong light which turns the liquid black. When the 

 sediment has settled, the supernatant fluid is withdrawn and replaced 

 by distilled water. This last process is repeated until the water no 

 longer shows a trace of colour. The water is then drawn oil*, the last 

 drops being removed by blotting-paper. To the moist sediment a few 

 drops of glycerin are added, and intimately mixed by stirring and by 

 rotating the vessel. The sediment is now ready for mounting. Instead 

 of glycerin, glycerin-jelly may be used. The cell-walls should be old 

 and thoroughly dry. The best cemeut for this purpose is made of zinc 

 oxide in a solution of dammar in chemically pure benzol to which 

 about j p.c. of old gilder's size and a much smaller quantity of castor 

 oil have been added. Such cells take from eight to twelve months to 

 dry properly, but are then as " permanent " as any mount can be 

 made. 



Staining Embryonic Cartilage.f — A. Moll stains embryonic carti- 

 lage with Tiinzer's orcein solution (orcein 0*5, absolute alcohol 40, 

 distilled water 20, hydrochloric acid 10 drops). The preparation (em- 

 bryos or pieces thereof) must be hardened in alcohol, and celloidiu sec- 

 tions immersed in the above solution for 6-24 hours. The sections 

 are then washed in 80-90 p.c. alcohol until the celloidin is almost 

 colourless ; after which they are dehydrated in 98 p.c. alcohol, cleared up 

 in origanum oil, and mounted in balsam. This method imparts a double 

 .stain, the preformed hyaline cartilage having a blue-violet hue and the 

 rest of the tissue being brownish-red. The stain affects the cartilage 

 matrix, the nuclei being red. Embryonic elastic cartilage does not give 

 the double stain. In adult cartilage the matrix is reddish and the 

 cartilage cells dark-blue. 



Staining Fluid for Counting Leucocytes.:": — Dr. R. Zollikofer uses 

 the following staining solutions to facilitate the counting and recognition 

 of the varieties of leucocytes. Solution A : — Eosin W.G. 0*05 ; formalin 

 1*0 ; distilled water 100. Solution B : — Methylen-blue 0*05; formalin 

 1*0; distilled water 100. When required for use equal quantities of 



* Amer. Mou. Micr. Journ., xxi. (1900) pp. 308-10. 

 t Centralbl. f. Physiol., xiii. (1899) pp. 225-6. 

 I Zeitscbr. wies. Mikr., xvii. (1900) pp. 313-21. 



