CHAPTER XIII. 
BACTERIOLOGICAL TECHNIQUE— Continued. 
THE CULTIVATION OF BACTERIA. 
In order to determine the number of living bacteria 
in any substance and their nature we have to cultivate 
and isolate them. 
The Most Common of the Nutrient Media Used for the 
Growth of Bacteria. . 
All of these must have, as noted earlier, food con- 
taining the necessary carbon, nitrogen, and mineral 
substances in a form easily assimilated and in the 
proper concentration. The pathogenic bacteria nearly 
all require for good growth peptone, albumins, and 
sugar. For each kind the proper food must be found 
through experimentation, as slight alterations may 
make a great difference. 
Physicians will find it, as a rule, convenient to 
purchase their media already prepared from some of 
the reliable firms that deal in bacteriological products. 
Special media, such as those employed for isolation and 
identification of the typhoid bacillus and gonococcus, 
will be found described along with those bacteria. For 
those who may wish to make their own, we will de- 
seribe here those in common use: 
Nutrient Bouillon or Broth. One part of finely chopped 
fresh, lean meat is macerated in two parts of water and 
