200 



G. G. Heslop: 



than the largest amount which has been shown not to interfere 

 with the complete haemolysis of the standardised haemolytic sys- 

 tem it has been titrated against. 



Having ascertained the exact quantity of each ingredient to 

 employ, the final test is now set up as follows, assuming for ex- 

 ample that the quantity of each ingredient shown below is the 

 titrated unit. 











^ 









s 

 ja 



3 



H 





rt S 

 a ™ c 



B M — 



c 



4) 



e 



"5. 

 So 



O <-l 



0> 



c 

 "3 



CO 



OO OS 



£«2 



Group 1. — 















Serum No. I (known 



1 - 



•15 



1 



15 ■ 



1-6 x 



b \ 



positive serum) 



2 



— 



•1 



15 • 



175 



•5 







3 ■ 



— 



*1 



— 



19 



•5 





Group II. — 

















Serum No. II. (known 



4 • 



•15 



•1 



15 • 



• 16 



g -5 





negative serum) 



5 • 



— 



•1 



15 ■ 



■ 175 



°b -5 



c^ 





C ■ 



— 



•1 



— 



19 



IS5-5 



« 



Group II [. — 













".S'S 



-M 



Serum No. III. (sus- 



7 



■ 15 



1 



•15 



- 16 



|S -5 



5 



pected serum to be 



8 ■ 



— 



•1 



15 • 



1-75 



%* '5 



3 

 O 



c 



tested) 



9 ■ 



— 



'I 



— 



- 1-9 



M -5 





Antigen control 



10 



- J5 







•15 



- 17 



•5 





.Complement control 



11 



— 



_ 



•15 



• 1-85 



•5 





Saline control 



12 



— 







— 



- 2- i 



•5J 





The first tube in each group of three contains antigen, and it 

 is therefore the tube in which the particular serum is being tested. 

 All other tubes in the series are controls. 



The second tube in each group of three is the serum control 

 for the particular serum of the group. This tube must show 

 complete haemolysis before the reaction of the particular serum 

 in the test can be recorded. 



The third tube in each group of three is also a serum con- 

 trol, but in this tube complement is omitted. This tube serves 

 as a control to show that the particular ox serum is not in itself 

 haemolytic for the unit of sensitised R.B.C. No haemolysis 

 should occur in this tube. After the first incubation for one hour 

 has taken place, one unit of sensitised red blood cells is added to 

 each tube, and the rack is then replaced in the incubator. The 

 duration of the final incubation period varies usually from 10 

 to 30 minutes, and the tubes have to be carefully watched in 

 order to note the appearance of haemolysis. Complete haemo- 

 lysis must have taken place in both the antigen and compelment 



