VI 



was retarded until the 13th day, approaching what is 

 the ease in tetanus and botulismus. 



The curve had often a very acute angular form in- 

 dicating that the amount of agglutinin was rapidly 

 increasing during a very short lime, for instance arise 

 was observed from 8 to 16,000, from 40 to 1820 etc., 

 and then the amount fell down again just as rapidly, 

 so that the initial ordinate of the curve was reached 

 again a few weeks after the injection. 



Under these investigations the individual differences 

 in the animals, which alway occur in the immunity 

 studies, were met with. 



An especially striking example is given by the three 

 rabbits, represented on curve No. 4. After quite a uni- 

 form treatment during 5 weeks, the agglutinating power 

 of No. I was 154, of No. II 40 and of No. Ill 8. An 

 equal amount of B. typhos. culture as used before now 

 produced such different fluctuations, that No. I reached 

 :>()<), No. II 1820 and No. Ill 30: yet the type of the 

 curve was equal for them all, the maximum being reached 

 nearly the same day. As a sign of the irregularities, 

 met with, it may be noticed, that it was not No. I (the 

 animal which possessed the greatest amount of agglu- 

 tinin at the beginning of the experiment) but No. II, 

 the curve of which was so much higher than the others. 



It might be of some interest to remember these facts 

 under the endeavour to draw the agglutinin producing 

 qualities into the means of distinguishing the different 

 bacilli of the typhoid- coli group. 



Two things must be considered. 1) The regular 

 fluctuations of the agglutinin curve, 2) The different 

 individuality of the animals. 



During the immunisation of horses against diphlhe- 



15 - 



