, 201 



Very good too seems to be the method, which Miss Van 

 RiEMSDIJK pubhshed some time ago in the »Centralblatt für 

 Bakteriologie.« 



With a strong agglutinable serum we certainly obtain again 

 and again very marked differences between diphtheria bacilli 

 und bacteria, which are more or less allied to them. It is my 

 experience though and, as the bacteriological literature teaches, 

 that of most experimentors, who have occupied themselves with 

 diphtheria agglutination, that most unexpected surprises are 

 obtained. Thus one culture possessing every possible character 

 of a diphtheria bacillus, virulence included, is not agglutinated, 

 as another strain which was thought to be one of pseudo- 

 diphtheria agglutinates very well indeed. This must of course 

 be due to the imcomplete working-method and we may expect 

 that the difficulties, that have presented themselves so far 

 will disappear. 



The precipitation reaction has not yet been able to find a 

 place in the examination of diphtheria either. We tried to 

 get something suitable out of the application of the thermo- 

 precipitation, with which Ascoli had such splendid results with 

 anthrax, but have failed so far. The complement fixation test 

 does not give any result equal to the very complicated techi- 

 nical difficulties of this method. 



It is much safer all round, to call in the assistance of the 

 experiment on animals. The diphteria bacillus is a toxin-producer 

 and this toxin is not only harmful to man, but may also be 

 very dangerous to a great many animals. In the guinea-pig 

 we find an animal which specially suits our purposes. If a 

 guinea-pig is injected subcutaneously with a sufficient dose of 

 a toxincontaining medium, it will die in a few days and on 

 obduction we will find the typical symptoms. If we bring only 

 a small quantity of the toxin under the skin, in the way RÖMER 

 suggested several years ago or after the method in which miss 

 VAN RiEMSDIJK made some technical improvements, we get a 

 very circumscript characteristic process on the skin. 



Although we shall find in this way a very excellent method 

 of identifying a culture of diphteria, still more important are the 

 results, that will be obtained by making use at the same time of 

 the property of the toxin of being neutralised by its antitoxin. 



