208 



cutaneous inoculation Our cultures proved non -pathogenic for 

 guinea-pigs. 



Now we had to do here with a small epidemic of throataffections, 

 which resemble diphtheria clinically ; the infection passes from 

 one person to another, but the virus is not very virulent to 

 man. In most cases bacilli are isolated from the throat, be- 

 having in every way like diphtheria bacilli, also as regards the 

 acid-production, but non-virulent to guinea-pigs. Now what had 

 we got here? I should like to say a diphtheria bacillus slightly 

 pathogenic to man and non-pathogenic to guinea-pigs. To 

 diagnose here that it were no diphtheria bacilli because the 

 guinea-pigs remained healthy seems to me too theoretical. 



It will be undertood now, that the absence of virulence for 

 guinea-pigs is not always easy to demonstrate and that a 

 negative result does not always prove a valuable help to iden- 

 tify the bacteria found. And above all if we think, that we obtain 

 these results only after several days, it will be clear that not 

 too much attention should be paid to the estimation of the 

 virulence for the practical diphtheria-diagnosis. 



On reading all this one may get the impression, that the 

 bacteriological diagnosis of diphtheria seems to be rather a 

 desperate thing. But as a rule this is not the case, as may 

 appear from the following lines. 



We shall have to draw a sharp line as to what is intended 

 at with the examination. There is namely a great difference 

 whether we get material for examination from diseased persons, 

 convalescents or healthy individuals. 



If a person is attacked by an affection of some mucous 

 membrane, which makes the general practitioner think of diph- 

 theria and if the doctor sends material for examination, the 

 diagnosis hardly ever affords many difficulties. If the method, 

 used in this laboratory is applied and if within 24 hours bacilli 

 are found, which are considered to be diphtheria bacilli and if 

 on account of this state of affairs and of the clinical observations 

 diphtheria is diagnosed, the chance of making a mistake is 

 exceedingly small. 



The same cannot be said of a negative result of the bacterio- 

 logical examination ; here we must bear in mind the possibility 

 of the material not being taken from the right place or desin- 



