BACTERIOLOGICAL TECHNIC. 



53 



the work of those who make bacteriology a specialty.. Such bacterial 

 cultures as are likely to come to the notice of pharmacists will most generally 

 be prepared by physicians, health officers, and other specialists in bacteri- 

 ology. The pharmaceutical bacteriologist may be called upon to make 

 bacterial examinations of drinking water, of milk, of ice cream, and other 

 food materials; of syrups, liquors, aquae, tinctures, fluidextracts, infusions, 

 etc., and he should, if possessed of some skill and adequate laboratory 

 facilities, be able to do so. 



The prime object in growing bacteria in artificial culture media is to 

 make possible their further more careful and more extended study. The 



t 



o 



i 



Fig. 29.— Cover-glass pincers, a and b are self-damping but the pressure is often enough 



to break thin covers. 



study of bacteria in their natural or normal surroundings is all-important, 

 but is not complete without the artificial culturing. 



As a rule, bacteria are biologically associated with other organisms, and 

 it is unusual to find pure cultures in nature or in natural media. An open 

 sore may contain several or many species and varieties of bacteria, in addi- 

 tion to the pus germs. The intestinal tract of the typhoid patient contains 

 bacteria other than the comma bacillus of Koch. The tubercular bron- 

 chials always show a mixed infection. The diphtheric membrane con- 

 tains some foreign germs, etc. Some infections, particularly those of 

 internal tissues or organs, as lymphatic glands for example, may present 

 practically pure cultures. However, no matter how mixed an infection 



