8 LABORATORY BACTERIOLOGY 
11. Work for this exercise. Make 1000 cc. of bouillon and 
distribute it as follows : 
Put 5 cc. in each of 10 small sterile test tubes. 
Put 300 cc. in each of 2 large (500 cc.) Erlenmeyer flasks, 
and the remainder in a third flask. 
Put 5 cc. of distilled water in each of 5 small sterile test 
tubes and sterilize them with the bouillon. (They are to be 
used subsequently in place of bouillon in making dilutions.) 
Label the tubes “ sterile distilled water.” All media required 
to carry out the directions will be furnished by the instructor 
excepting such as the student is directed to make in Exercises 
III, IV, and X. 
12. The preparation of bouillon. Take 500 grams of lean 
beef, remove all fat, and grind it in a sausage machine or have 
it minced at the butcher shop. Place the minced meat in an 
agate-iron dish, add 1000 cc. (2 parts water to one of meat)- 
of clear boiled water, cooled to 65° C., and stir thoroughly 
with a glass rod. Then macerate it, with frequent stirring, in 
a water bath at a temperature of 60°C. for one hour after the 
temperature of the meat and water reaches that of the water 
outside or, to save time, at a temperature of 65° C. for 30 
minutes. Remove the meat by straining the liquid through a 
piece of cheese cloth. For this a stout iron meat press is 
desirable. Boil the strained meat infusion for 20 minutes.’ Cool 
to harden the fat, and filter through filter paper. The filtrate 
should equal in quantity the amount of water used ; if it does 
not, add enough distilled or clear boiled water to make up that 
amount. To this meat infusion add 1% peptone (Witte’s) 
and 4% sodium chloride. Add enough of a normal solution 
of sodium hydrate to give the liquid a faintly alkaline reaction 
when litmus is used as an indicator. (For method of titrating 
media, see § 14.) The infusion is then boiled in a water bath 
1 In case of a short period, the exercise may be divided at this point 
by boiling the infusion for 30 minutes and keeping it overnight. The 
receptacle should be covered. 
