EQUILIBRIA IN ABSORPTION PROCESSES 165 



high degree the flocculation in a culture containing living 

 coli bacilli treated with the same agglutinin. One might 

 replace the bacilli with some fine inert powder, e.g. tal- 

 cum ; this fine powder would then, just like the bacilli, be 

 jammed together by the coagulum in their neighbourhood. 

 Therefore the deposits containing bacilli are more volu- 

 minous than those of the fluids from which the bacilli are 

 removed by filtering. The liquid which is coagulated by 

 the agglutinin is according to Nicolle very resistant to low 

 and high temperatures. It is soluble in alcohol and to a 

 certain degree in ether, so that an extract from the bacilli 

 in one of these fluids yields, after evaporation to dryness 

 and dissolution in a weakly alkaline bouillon, a flocculent 

 deposit on treatment with its agglutinin. 



This coagulable substance is prepared in the interior of 

 the bacilli which contain it, and it is even partially given 

 up to the surrounding medium, as is indicated by the 

 experiments of Kraus. Agglutinins are contained in 

 normal sera, as for instance in the horse, the blood-serum 

 of which agglutinates cholera vibrios to a high degree, 

 and less effectively cultures of Vibrio Metschnikovi, typhoid 

 bacilli, colon bacilli, and tetanus bacilli as well as strepto- 

 coccus. The normal sera of different animals agglomerate 

 the normal erythrocytes of other animals, as, for instance, 

 the serum from the horse agglutinates erythrocytes from 

 guinea-pigs or rabbits. In these cases, just as with the 

 agglutinins acting upon microbes, it is possible to increase 

 the content of the specific agglutinin in the normal serum 

 by repeated injections of the erythrocytes in question. 



Even simple chemical reagents cause an agglutination 

 of bacilli, thus, for instance, typhoid bacilli are agglutinated 



