188 APPLIED BACTERIOLOGY 



if slightly alkaline, but more rapidly on agar at blood-heat, 

 but the colonies so produced have no special characters. 

 On potato there is hardly any visible growth, unless the 

 potato be first moistened with beef-broth, in which case the 

 growth is both rapid and visible. 



On blood serum or glycerine-agar it grows with great 

 rapidity, but the best medium of all is that devised by Loffler, 

 who uses equal parts of serum and broth, with 8 per cent, 

 of grape-sugar (this mixture is, of course, sloped and heated 

 to ' set ' it before use). 



The growth appears as a cream-coloured streak along the 

 line of the inoculation, and is so rapid as to be plainly 

 visible to the naked eye twelve hours after the inoculation, 

 provided the tube is kept at blood-heat. 



In addition to the actual streak produced where the wire 

 touched the medium, there wiU be noticed a number of 

 small isolated dots, near to, but not touching, the actual 

 streak. This appearance, as well as the rapidity of 

 the growth, is characteristic of the Klebs-Lbffler bacillus, 

 but neither can be relied on as a certain indication 

 till confirmed by a microscopic examination of stained 

 specimens. 



Some observers state that it is possible, by rubbing a 

 sterile wire on an inoculation streak only four hours old, 

 long before any visible growth has appeared, to obtain 

 sufficient material to permit a correct microscopical diag- 

 nosis, even when the bacillus could not be demonstrated by 

 direct staining of the membrane. 



In the false membrane the Klebs-Lofiler bacillus is 

 associated with several organisms, the principal being the 

 staphylococci and the Streptococcus pyogenes. It not 

 infrequently happens that in the early stages of diphtheria 

 the bacillus cannot be demonstrated, and any case that 

 presents the clinical symptoms of diphtheria should be 



