174 APPENDIX. 
Wash in running water from twelve to 
twenty-four hours. Preserve in 80 per cent. 
alcohol. 
17. Cleaning Mixture, for Slides, Cover- 
glasses, and Glassware. 
Potassium bichromate, 6 gm.; 
Sulphuric acid, 6c¢.3 
Water, 100 ¢.c. 
Wash in water and alcohol. 
18. Nessler’s Solution. 
A. Potassium iodid, 35 gm.; 
Water, 200 €.¢. 
B. Mercuric chlorid, 16 gm. ; 
Water, 500 ¢.c. 
Add B to A until faint show of excess is 
indicated, then add 160 grams of solid 
potassium hydrate. Dilute to x liter, and 
add strong solution of mercuric chlorid, 
little by little, until the red mercuric iodid 
just begins to be permanent. Do not filter. 
Solution should be pale straw-color. It is 
improved by age. 
19. Phenol-sulphonic Acid. 
Sulphuric acid (pure and 
concentrated), 148 c.c.; 
Distilled water, 12 Ges 
Pure carbolic acid, 24 gm. 
