203 



After a certain time, varying from i8 to 24 hours, both media 

 are examined. If there are separate colonies, which look very 

 much like diphtheria colonies, microscopical preparations are made 

 of them. If this is not the case and such colonies are not clearly 

 visible we make a preparation of material taken from different 

 parts of the plate. These films are stained by the new method 

 of Neisser with the modification of GiNS. If trained assistants 

 find bacilli which have the typical shape of diphtheria bacilli 

 and contain the bodies of BabeS-Ernst, then the diagnosis 

 diphtheria is made. 



By proceeding in this way we make use of the property of 

 diphtheria bacilli to grow rapidly and abundantly on Loeffler's 

 serum at body temperature in the shape of characteristic colonies 

 and to exhibit within 24 hours by NeiSSER's stain very typically 

 the metachromatic bodies. 



May we be perfectly sure now by working in this way that our 

 diagnosis is the right one and that no diphtheria bacillus escapes 

 our attention? I should be the last to be positive as to that. 

 As mentioned before we only get near the truth and I am 

 convinced that in proceeding like this, a mistake is made 

 occasionally in one direction or the other. 



Being convinced of this it is easy to understand that people 

 will try by all means to extend and improve upon the working 

 methods. But at the same time the question arises whether the 

 improvement achieved is proportional to the possibly longer 

 duration of the examination. The solving of this problem will 

 be the subject of the following lines. 



In the first place let us pay attention to these modifications 

 or extensions of the technical part which do not lead to prolong 

 the examination. Over and over again it has been tried to find 

 a culture medium able to stimulate the growth of diphtheria 

 bacilli and to inhibit at the same time the growth of other 

 microorganisms, specially those who are nearly related to 

 diphtheria bacilli. Of the methods, which have been published 

 recently, I should like to mention those of RaNKIN and of 

 Conradi-Troch. None of these culture media however came 

 up to the expectation and up to the present the best results 

 have been obtained with Loeffler's serum. 



When the staining method of Neisser is used it is considered 



