658 THE PARASITIC HYPOMYCETES 



resistant to the decolourizing action of acid as the tubercle bacillus. The 

 clubs stain with picrocarmine, safranin or eosin. A fresh specimen stained 

 with picrocarmine shows the clubs detached and stained yellow on a pink 

 background of cells. 



Colonies crushed between slides may be stained, after drying and fixing in 

 alcohol-ether, by Gram's method and counter-stained with eosin. The 

 filaments will be stained violet and the clubs yellow or pink (fig. 308). Sec- 

 tions may be stained in the same manner. Weigert's method may also be 

 used. 



Equally pretty preparations may be obtained by staining sections for 

 30-50 minutes in carbol-fuchsin, decolourizing rapidly in 1 per cent, sulphuric 

 acid, washing in alcohol, then in water, and counterstaining with an aqueous 

 solution of methylene blue. 



IK- -' - -Vtfr 



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" f & 3 4 *5.# *JP^ f*St. ? * JW 



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FIG. 309. Discomyces bovis. Section through a bovine lesion. Carbol-fuchsin 

 and methylene blue. (Oc. 2, obj. T \th, Zeiss.) 



Morel and Dulaus recommend the following technique for sections : Stain for a 

 few minutes in Delafield's haematoxylin (acetic acid is added until the solution has 

 a red tint). Wash in water. Treat for 3 minutes in the following solution : 



Victoria blue, - 1 gram. 



Alcohol, - 10 c.c. 



Water, - 90 



Wash again. Treat with Gram's solution for a few moments. Wash in alcohol. 

 Stain for a few minutes in : 



Rosalin-violet, - 1 gram. 



Alcohol, - 10 c.c. 



Water, - 90 



Wash in water again. Pass rapidly through absolute alcohol. Decolourize 

 very rapidly in a mixture of equal parts of essence of cinnamon and absolute alcohol. 

 When the sections have acquired a red colour wash in alcohol, clear in xylol and 

 mount in balsam. The nuclei of the cells are violet, the mycelium of the parasite 

 blue, the clubs bright red. 



For staining pus when no yellow grains can be found with the naked eye, Lemiere 

 and Becue recommend the following method : 1. Spread a little of the pus on a 

 slide, dry and wash in ether. 2. Treat for a few minutes with a 30 per cent, solu- 

 tion of soda. 3. Stain for a quarter of an hour in a 5 per cent, aqueous solution of 

 eosin. 4. Wash in a saturated aqueous solution of sodium acetate and examine 

 the preparation in this solution. The centres of the colonies are red, the clubs 

 pale yellowish-pink. 



