212 BACTERIAL VACCINES 



or pyelitis by securing urine with the aid of a sterilized catheter. If 

 slowly growing organisms, such as Bacillus influenzse, gonococcus, 

 pneumococcus, etc., are to be cultured, " streak" plates are usually sat- 

 isfactory, and as a routine the best culture-media are, as a rule, those 

 containing serum or blood. 



3. The cultures that are to be worked up into a vaccine are usually 

 best made on solid media. 



4. In making a bacterial vaccine of a freely growing microorganism 

 for an individual patient, it will suffice to plant two agar slant tubes; 

 when .dealing with bacteria that grow much less luxuriantly, such as 

 streptococci and pneumococci, four to six tubes should be used. 



5. Cultures are usually grown for twenty-four hours at 37 C., but 



FIG. 57. PREPARATION OF A BACTERIAL VACCINE. 



Removing the culture of bacteria by gently rubbing over the medium (agar-agar) 

 with a sterilized platinum loop. 



in the case of rapidly growing organisms a shorter period in the in- 

 cubator will suffice. 



6. When the cultures are ready, a smear of each growth is made and 

 stained in order to see that pure cultures of the right microorganism were 

 made. 



7. Inasmuch as the immunizing power of a vaccine is in most cases 

 a factor of the virulence of the organism, this being especially true of 

 such organisms as the pneumococcus, streptococcus, and influenza 

 bacillus, it is well, whenever possible, to employ the first pure subculture 

 for the preparation of the vaccine. 



3. Preparation of the Emulsion. Carefully observing aseptic pre- 

 caution throughout, pour a portion of a test-tube of a sterile normal salt 

 solution over the surface of the first culture, shaking the fluid in such a 



