BACTERIUM INFLUENZA 427 



matter has been added. Its cultivation is best conducted 

 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 

 placed in the incubator at 37 to 38 C. If influenza bacilli 

 be present, they will develop as minute, transparent, watery 

 colonies that are without structure, and which resemble 

 somewhat minute drops of dew. They are discrete and 

 show little or no tendency to coalesce. 



If a small bit of mucus be rubbed over the surface of 

 ordinary nutrient agar-agar, no such colonies develop. 

 In making the diagnosis by this method cultures on both 

 agar-agar containing blood (not blood-serum) and agar- 

 agar containing no blood should always be made, for the 

 reason that growth of these peculiar colonies in the former 

 and no such growth in the latter are evidence that one is 

 dealing with the organism under consideration. 



The organism may also be cultivated in bouillon to which 

 blood has been added, if kept at body-temperature. The 

 growth appears as whitish flakes. Since this organism is 

 a strict ae'robe, its cultivation can only be conducted on 

 the surface of the medium used i. e., where it has freest 

 access to oxygen. It is therefore inadvisable to prepare 

 plates in the usual way. When its cultivation is attempted 

 in bouillon it is recommended, in order to favor the free 

 diffusion of oxygen, that the depth of fluid be very shallow. 



Contrary to what might be supposed, bacterium influenzse 



