160 APPLIED BACTEEIOLOGY 



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 will 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-Loffler 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-Loffler bacillus is 

 associated with several organisms, the principal being the 

 staphylococci and the Streptococcus pyogenes. This latter 

 organism has so often been found in the false membrane 

 as to be believed by some observers to be the specific cause 

 of diphtheria. It not infrequently happens that in the 

 €arly stages of diphtheria the bacillus cannot be demon- 

 strated, and any case that presents the clinical symptoms 

 of diphtheria should be treated as such, whether the bac- 

 teriological examination enables us to detect the bacillus or 

 not. On the other hand, bacteriological diagnosis will often 

 insure the recognition of a case of true diphtheria, in which 

 the clinical symptoms are ill defined, and which might, 

 though slight in itself, give rise to severe cases. After an 



