BACTERIUM INFLUENZA 401 



should be pale red). (Fig. 76.) It is decolorized by the 

 method of Gram. 



It develops only at temperatures ranging from 26 to 

 43 C. Its optimum temperature for growth is 37 C. It 

 possesses the peculiarity of developing upon only those 

 artificial culture-media to which blood or blood-coloring- 

 matter has been added. Its cultivation is best conducted 



t 



FIG. 76 





, *H? *v 



Bacterium influenzae in sputum. 



and its development most satisfactorily observed by the 

 following procedure: over the surface of a slanted agar tube 

 or over agar-agar solidified in a Petri dish smear a small 

 quantity of sterile blood (not blood-serum). A bit of the 

 mucus from the sputum of the influenza patient is then 

 taken up with sterilized forceps or on a sterilized wire loop, 

 rinsed in sterile bouillon or water and rubbed over the sur- 

 face of the prepared agar-agar. The plate or tube is then 

 26 



