\ 



290 THE ROLE OF AGGLUTINATION IN IMMUNITY, 



precipitate. I pointed out that in conformation with the known 

 facts of precipitation, the agglutinated substance would form first 

 on the flagella on account of their relative fineness, and the 

 motility of the microbe would cease owing to the coated flagella 

 being flocculated, i.e., drawn together. G. de Rossa* finds that 

 the flagella are exceedingly sensitive to the agglutinins of specific 

 sera. As it was Kraus' precipitate that was formed on the 

 flagella and capsules of the bacteria, it is interesting to note that 

 Krausf retracts a former conclusion of his that precipitins and 

 agglutinins are different substances, and now considers that they 

 are the same. I also clearly indicated the role of salts in the 

 phenomenon, which I considered to be simply a case of chemical 

 flocculation concerning which I had previously written.l My 

 conclusions have been confirmed by the physical researches of 

 Bechhold.§ Soon after the publication of my paper, Joos and 

 Friedberger contributed papers emphasising the function of salts. 

 In a later paper, jj I criticised the interpretation of their investi- 

 gations, and at the same time showed the fallacy of Harrison's 

 conclusions that the agglutinable substance is contained in the 

 outer membrane of the microbic cell. 



The actual observation of a precipitate with the imbedded 

 bacteria was first seen by Lowit,1i who was able to colour the 

 precipitate and at the same time to diff'erentiate the bacteria in 

 the matrix by the Nocht modification of the Romanowsky stain. 

 I have also been able to demonstrate the precipitate in much the 

 same way. Typhoid bacteria, which had been grown in heated 

 agglutinating serum, were found to be firmly held together. The 

 clumps were broken up and washed four times with normal 



* Centrb. f. Bakt. Orig. xxxvi. (1904) 685 and xxxvii, (1904) 107. 

 t Ihid. xxxvi. (1904) 662 and xxxvii. (1904) 73. 

 X Journ. Soc. Chem. Ind. 1898, xvii. 117. 

 § Z. physik. Chem. 1904, 48, 385, through Journ. Soc. Chem. Ind. 1904^ 

 xxiii. 730. 



II These Proceedings, 1902, 66. 

 IT Centrb. f. Bakt. Orig. 1903, xxxiv. 156, 251. 



