Agglvfhiation Text in Ahortioii. oB-f 



<iuaiititv of ililuted soniui, heiift' it is advisahU' to n-for to the- 

 agglutinating titre of a serum as " so many cul)ic (.-(.'iitinietres of 

 serum,'" and not us " up to a dilution of such and such." Foi- 

 the statement of the dilution to ho of any guide to other workers 

 this must be supplemented by a statement referring not only to th& 

 actual amount of diluted serum used, but to the actual quantity 

 of emulsion used also. 



Adopting the suggested method — i.e.^ the statement of the exact 

 Huantity of serum used, the amount of emulsion used is the only 

 supplementary factor required to be known, for, as is shown by 

 these experiments, and by the following section, the amount of 

 emulsion markedly and in a regular manner affects the agglutina- 

 tion titre. 



b. — Influence of Qtia/it/f// of Emulsion on Agglutination. 

 Also a note on a peculiar it >/ of agglutination. 



As is indicated in the experiments in sub-section (a) of section 5 

 of this paper, the quantity of emulsion present in a tube in which 

 there is a certain definite amount of serum (or, in other words, 

 the proportion between the amount of emulsion and the amount 

 of serum), has a bearing on whether that particular quantity of 

 serum will show agglutination of the bacilli or not. 

 whereas with 0.05 c.c. of emulsion (Standard 10 X) agglutination 



The tests, la. and lb. (see Conclusion 3, page 382), showed that 

 occurred with quantities of serum varying from 0.006 c.c. up, with 

 0.1 c.c. of the same emidsion the smallest quantity of serum to giver 

 agglutination was 0.02 c.c. 



To further elucidate this relationship, a large number of tubes, 

 with varying proportions of emulsion and serum, were put up as 

 indicated in the table (Table 2), in which the results are also 

 shown. On account of the wide range in quantities over which 

 the experiment Avas made, various concentrations of serum and of 

 emulsion were used in actually making the test. 



These basal dilutions Avere : — 



Of Serum : — 1 in 5. 1 in 50, and 1 in 500. 

 Of Emulsion: — A standard suspension "X," and also one 

 standardised to 10 X — i.e., 10 times as strong. 



The quantities of emulsion used are stated throughout the table 

 in terms of standard X enmlsion, but for those tubes shown in 

 the table as containing 1 c.c. and over of standard X emulsion, the 

 10 X emulsion was used; the amounts of this (standard 10 X) that 



