214 BACTERIOLOGY. 
to give it the desired reaction, which is for most bac- 
teria slightly alkaline to litmus. If the fluid is clear 
it is put into flasks and tubes and sterilized; if not 
clear, the white of one or two eggs is added to the 
fluid after cooling it down to about 55° C. After 
Fig. 21. 
Autoclave for sterilization with live steam under pressure. 
thoroughly mixing the eggs the bouillon is boiled 
briskly for a few minutes and then again filtered and 
distributed in flasks and tubes and put in the Arnold 
sterilizer for one hour on each of two consecutive days, 
or in the autoclave for twenty minutes for sterilization. 
Instead of meat 2 to 4 grammes of Liebig’s or some 
other meat extract are added to each litre of water. 
For most purposes the extract is as good as the fresh 
meat, but for toxin production it is inferior. 
