APPARATUS AXD REAGENTS. 53 



Bismarck brown. 



(a.) Dissolved in equal parts of glycerine and alcohol. 

 (/>.) Dissolved in glycerine, two to four per cent, solution. 

 (c.) Aniline brown, . . . . i part. 



Alcohol, anhydrous, . . .10 parts. 



Distilled water, . . .100 parts. 



The (c) solution answers best for most purposes, though 

 either of the above does well. The more dilute the stain, and 

 the longer the staining process, the better the results. 

 Cedar oil, clove oil, bergamot oil, and xylol. 

 Turpentine. 

 Glycerine. 

 Dammar varnish. 

 Canada balsam dissolved in turpentine, benzole, or xylol. 



Summary of Process of Examination of Fluids or Tissues for 



Micro-organisms. 



37. Examine in a fresh condition fluid scraped from an organ or 

 taken from a cultivation (§ 31, p. 45). Treat with various reagents 

 (§ 21, p. 24). Dry and coagulate by heat and stain (§ 22, p. 26), or 

 stain by His's method, if there is no albumen in the fluid (§ 32, 

 p. 46). 



Stain with methyl blue (watery solution) or some other aniline 

 staining fluid, and mount at once in glycerine. 



It is often a good plan to overstain, and then, before mounting, 

 to wash out the excess of stain with a dilute solution (ten per cent.) 

 of acetic acid. 



After staining, wash off excess of fluid or of acid with distilled water 

 (Fig. 13). Examine the specimen at once, or dry and mount in 

 balsam. 



Examine fresh sections or pieces teased out, both unstained (§ 21, 

 p. 24) and stained (§ 24, p. 31, and § 25, p. 35) ; use various re- 

 agents (§21, p. 25). 



Harden pieces of the tissue (§ 33, p. 47), and cut sections. 



Soak in absolute alcohol. 



Stain with gentian violet (§ 25, p. 35) 



Wash in iodine and iodide of potassium solution (§ 25, p. 35). 



