46 The Philippine Journal of Science isie 



puscles for five hours failed to reactivate the amboceptor. This 

 was probably due to the disappearance of complement. 



Technique. — A quantity of fresh human serum was divided 

 into three portions designated as A, B, and C. Portion A re- 

 mained unheated, portion B was heated to 55 °C. for thirty 

 minutes, and from portion C the natural antiguinea pig ambo- 

 ceptor was removed in the following manner. One cubic centi- 

 meter of unheated human serum was diluted with 1 cubic centi- 

 meter of physiologic salt solution and was placed in cracked 

 ice. For each tube with diluted serum a centrifuge tube with 

 3 cubic centimeters of washed guinea pig corpuscles was also 

 placed in the cracked ice. After having stood in the cracked 

 ice for fifteen minutes, the serum was mixed with the corpuscles 

 in the proportion of 2 cubic centimeters of diluted serum to 3 

 cubic centimeters of corpuscles. These mixtures were allowed to 

 remain in the cracked ice for three hours and were then removed 

 and centrifuged; the clear serum was pipetted off and was used 

 as complement. The complement was carefully tested for am- 

 boceptor; the dose of 0.8 cubic centimeter mixed with the test 

 dose of corpuscles failed to produce haemolysis. 



Now it was attempted to reactivate the heated human serum 

 with the human complement and with guinea pig complement. 



Three sets of tubes, designated A, B, and B', were prepared. 

 Each set contained four tubes marked 1, 2, 3, and 4. Tubes 1, 

 2, 3, and 4 of set A received 0.4, 0.2, 0.1, and 0.05 cubic centi- 

 meter of serum A, respectively. To each tube was added 0.5 

 cubic centimeter of 4 per cent suspension of guinea pig cor- 

 puscles and enough salt solution to make the total quantity 2.5 

 cubic centimeters. Set B received serum B and complement C. 

 Tubes 1, 2, 3, and 4 received 0.4, 0.2, 0.1, and 0.05 cubic centi- 

 meter of heated serum B and 0.4, 0.2, 0.1, and 0.05 cubic centi- 

 meter of complement C, respectively. Each tube received 0.5 

 cubic centimeter of 4 per cent suspension of guinea pig cor- 

 puscles and enough salt solution to bring the total quantity up 

 to 2.5 cubic centimeters. In set B' serum B and guinea pig 

 complement were used. Tubes 1, 2, 3, and 4 received 0.4, 0.2, 

 0.1, and 0.05 cubic centimeter of heated serum and 0.4, 0.2, 0.1, 

 and 0.05 cubic centimeter of fresh guinea pig serum, respec- 

 tively. The usual test dose of guinea pig corpuscles was added 

 to each tube, and the total quantity in each tube was brought 

 up to 2.5 cubic centimeters with physiologic salt solution. After 

 shaking, the tubes were put in the incubator at 37 °C. for one 

 hour and then removed to room temperature; the results were 

 read about three hours after the corpuscles had been added. 



