EQUILIBRIA IN ABSORPTION PROCESSES 157 



looking through the tube against a printed paper and 

 expressed corresponding to one of the four following 

 degrees : Liquid completely clear, perfect agglutination ; 

 Most bacteria subsided, but liquid not wholly clear, strong 

 agglutination; Some bacteria subsided and agglomerated, 

 no clearing of the liquid, weak agglutination; No appre- 

 ciable change of the liquid, no agglutination. 



In other experiments the bacteria used had been treated 

 with serum containing agglutinin, nitrate of lead, ferric-sul- 

 phate, alcohol, acids, or uranium acetate (which all agglu- 

 tinate them), and thereafter thoroughly washed until the 

 wash-water did not show any reaction of the agglutinating 

 substances. The bacteria treated in these different man- 

 ners may be called sero, lead, iron, alcohol, acid, and 

 uranyl bacilli respectively. The bacteria had then been 

 altered so that they behaved in a different way to salt- 

 solutions than did the original bacteria. On the addition 

 of sulphuretted hydrogen to the bacteria treated with lead, 

 these were coloured black, which proves that the bacteria 

 had retained the lead in spite of the washing. For a com- 

 parison Bechhold 1 examined the behaviour of suspensions 

 of mastic, prepared by adding some drops of an alcoholic 

 solution of this material to water (so-called "a mastic"), 

 or some drops of water to the alcoholic solution (" (3 mas- 

 tic "). The experiments on the agglutination of this last 

 emulsion were done at ordinary room temperature, as the 

 suspended matter would dissolve at 37. 



In the first place an influence of the time of reaction 

 was noted. Suspensions of sero-bacilli mixed with 0.05, 

 0.025, or 0.012 normal solutions of sodium chloride or 



1 Bechhold: Zdtschr . f. ph. ^.,48.385 (1904). 



