3 o8 
LABORATORY WORK. 
Forceps Common and Cornet forceps. 
Microscope with 1/12 immersion lens and plenty of slides 
and cover-glasses. 
MATERIALS. 
Peptone (Witte) 
Salt 
Beef extract 
Gelatin Gold label 
Agar-agar 
Litmus, dry in cubes 
Absorbent cotton 
Fuchsin 
Dextrose, lactose, and 
saccharose 
Normal NaOH and Normal 
HC1. 
Phenolphthalein 
Alcohol 
Corrosive sublimate 
NaOH 
HCI 
Azolitmin 
Methylene blue 
Common cotton, good quality 
No. i. Washing and Sterilizing Glassware. All glass- 
ware must be thoroughly washed in hot water and soap. 
New glassware should first be treated with i per cent. HCI. 
Used glassware, 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. 
i. To begin with, the student may wash 50 test-tubes, 2 one- 
liter flasks, one dozen Petri dishes and several i c.c. pipettes. 
After drying, place the pipettes in glass holders or a metal 
box, plug the test-tubes and flasks tightly with cotton and 
place these with the Petri dishes in the sterilizing oven. 
Heat for one hour at 310 F. (155 C.) for one hour. All 
glassware should be subsequently sterilized in the same 
way before using. 
No. 2. Preparation of Agar Culture Medium and Bouillon. 
Measure out the following: 
Water 
Liebig's extract of beef . 
Common salt . . . . . 
Peptone 
. i liter 
. 3 grams 
. 5 grams 
. 10 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. Dissolve the mixture at about 150 F. (6oC.). Add 
6 grams of agar-agar (1.2 percent.), cut into small pieces, and 
dissolve by heat. It takes considerable heat to dissolve the 
agar and may require boiling. Boil till the agar is com- 
pletely dissolved and then replace the water that has evaporated by adding 
cold water till the original weight has been restored. 
FIG 56. 
i c.c. pipettes 
inclosed in 
glass tubes for 
sterilizing. 
