138 MICROBIOLOGY 



The staining fluid is made up as follows: 



Azur Il-eosin 3 grams 



Azur II 8 grams 



This mixture is thoroughly dried over sulphuric acid in 

 a desiccator, finely powdered, and rubbed through a fine 

 sieve. It is then dissolved in 250 grams of C. P. glycerin 

 (Merck), at 60 C. To this is added methyl alcohol (Kahl- 

 baum) 250 cc. previously warmed to 60 C. This mixture is 

 well shaken and allowed to stand at room temperature for 

 twenty-four hours. The mixture is then ready for use. 



When used, 10 cc. of distilled water are poured into a 

 test tube and one to two drops of a one per cent potassium 

 carbonate solution are added. Ten drops of the staining solu- 

 tion described above (one drop to the cc.) are mixed with this 

 slightly alkaline w r ater. The preparation which is to be 

 stained is fixed in methyl alcohol, dried, and covered with the 

 diluted staining solution. For the staining of protozoa and 

 exudates containing bacteria, ten to fifteen minutes are suffi- 

 cient. For the staining of Negri bodies or Treponema pallida, 

 one or more hours of staining should be employed. After 

 staining, wash in running tap water, blot, dry and mount. 



Stains for blood preparations. These are often valuable 

 for certain bacteriological examinations and in studying the 

 blood in cases of infection. 



Jenner's stain. 6 Jenner's stain is one of the most rapid 

 and easy to manipulate of the many methods in use and 

 stains each of the several kinds of granules in the leucocytes. 

 It is recommended for ordinary examinations. The staining 

 fluid is a five-tenths per cent solution of the dye (Gruebler's) 

 in pure methyl alcohol (Merck's). This acts as both fixing 

 and staining fluid. The smear, previously unfixed, simply 

 dried in the air, is flooded with the staining fluid which is 

 allowed to act two or three minutes, when it is washed in dis- 

 tilled water until the better spread portions have a pinkish 

 tint, which usually requires about ten seconds. The water 

 Jenner. Lancet, 1899, i. p. 370. 



