332 
Fic. §5.— 
I c.c. pipettes 
inclosed in 
glass tubes for 
sterilizing. 
LABORATORY WORK 
Counting plate or counting card. 
Platinum wire to be fused into glass rods. 
Culture oven with constant temperature of 98°, 
Bunsen burners. 
Forceps—-Common and Cornet forceps. 
Microscope with }42 immersion lens and plenty of slides and 
cover-glasses. 
MATERIALS 
Peptone (Witte) Normal NaOH and Normal HCl. 
Salt Brom thymol blue 
Beef extract Xylol 
Gelatin—good grade Alcohol 
Agar-agar Corrosive sublimate 
Litmus, dry in cubes NaOH 
Absorbent cotton HCl 
Fuchsin Azolitmin 
Dextrose, lactose, and Methylene blue 
saccharose Phenolphthalein 
Common cotton, good quality. 
No. 1. Washing and Sterilizing Glassware.—All glassware 
must be thoroughly washed in hot water and soap. New glass- 
ware should first be treated with 1 per cent. HCl. Used glass- 
ware, containing remains of gelatin or agar, should first be boiled 
in water containing powdered soap or sal soda. Follow this with 
thorough washing in hot water, rinsing in cold water and draining. 
To begin with, the student may wash 50 test-tubes, 2 one-liter 
flasks, one dozen Petri dishes and several 1 c.c. pipettes. After 
drying, place the pipettes in glass holders or a metal box, and 
place these with the Petri dishes in the sterilizing oven. Heat for 
one hour at 310°F. (155°C.) for one hour. All pipettes and Petri 
dishes should be subsequently sterilized in the same way before 
using. 
No. 2. Preparation of Agar Culture Medium and Bouillon.— 
Measure out the following: 
Water... ccc cece cece cece cece eter e eee eennes t liter 
Liebig’s extract of beef... . 2... eee eee ee 3 grams 
PEPtONe.... cece cece cee eee cere cece ene e eens IO grams 
(a) Divide in two lots, set one-half aside (see below); place 
the other half in a stew-pan and carefully weigh the dish and its 
contents, noting the combined weight for future use. Add 7.5 
grams of agar-agar (1.5 per cent.), cut into small pieces, and 
