Agf/latiiuition Test In A hurt ion. 



:58<) 



The deposit following agglutination sliovild l^e siich that it can 

 be easily distinguished l)y the naked eye, even though, as is fre- 

 quently tlie case, the whole of the organisms be not sediniented. 



In the absence of deposit — i.e., in a negative agglutination re- 

 action, there should be surli a cjuantity of emulsion that a tulie 

 containing it can l)c easily distinguished from a tul)e not contain- 

 ing any emulsion. 



It is (if interest here to note the naked eye ap]ica)'ance of the 

 emulsion controls to the sets of tutes under review. 



In four of these controls the total volume of fluid was made up to 

 2 c.c, with carbolised saline: in the other four to 20 c.c. 



Of tho.se enndsion controls containing 2 c.c. of total fluid, it 

 will be seen that (1) and (2) above possess sxich a degree of cloudi- 

 ness that they are readily distinguishable to the naked eye as 

 containing emulsion. 



These tubes contain 0.05 c.c. and 0.02") r.c. respectively. 



In Sets I., II., and III., of agglutination results I'ecorded above 

 the smallest deposit (positive agglutination), wliich is easily read 

 (tubes containing 2 c.c. of fluid), is that where there is 0.025 c.c. 

 of emulsion. 



In Set IV.. tlie oidy tu])c where (although tliere was tlio same 

 quantity of serum in each tu])e), agglutination was manifest in 

 24 hours, was that one in wliicli tlierc was 0.05 c.c. of emulsion in 

 the tube. 



With tliis large volume of fluid (20 c.c), no smaller quantity 

 gave a completed reaction in 2-1 liours. 



From tliese experiments, therefore, it has l)een conchuled that tlie 

 optimum amount of enudsion to use- is 0.05 c.c. of " Standard 

 10 X '' emulsion (or 0.5 c.c. of " Standai'd X " cnuilsion). 



This amount, 0.5 c.c. of " Standard X " emulsion has, thei'e- 

 fore, been ado])ted foi- use in all pi-actical diagnostic tests for the 

 reasons that — 



