AMBOCEPTORS AND COMPLEMENTS 853 



(d) Has hemolysis occurred with the corpuscles used in treating 

 the serums and why? 



(e) Of what practical importance are natural hemolysins? 



(f) Is natural antihuman hemolysin ever found in human serums? 

 What are they called? 



Note. The quantity of natural amboceptor in any of these serums 

 may be determined by the method of titration given in the text. In 

 choosing five serums at random it may be possible that some will not 

 show an appreciable amount of natural antisheep amboceptor. 



EXERCISE 32. AMBOCEPTORS AND COMPLEMENTS (Continued) 

 EXPERIMENT 80. HEMOLYTIC COMPLEMENT 



1. After giving a rabbit three intravenous injections of 5 c.c. of a 10 per cent, 

 suspension of washed sheep cells at intervals of three days, remove three cubic centi- 

 meters of blood from an ear and separate the serum. Dilute the serum 1:10 with 

 salt solution. ^ J \\ * 



2. ^ntb^fou^t&fc-tubes- place 1 e-.fc. of a 2}/ per cent, suspension of sheep corpuscles 

 and increasing amounts of the above dilution 1 of rabbit serum ^(must be fresh ^ot 

 over twelve hours old) as follows: 0.4, 0.8, 1, a<d"2 c';c.j add sufficient salt solution. 

 Shake and incubate for one hour. 



(a) Has hemolysis occurred? 



(b) How do you explain the reaction? 



(c) From where was the complement derived? 



(d) Are complements found in the bloods of all animals? 



(e) Discuss the question of the multiplicity of complements. 



EXPERIMENT 81. IN ACTIVATION AND REACTIVATION OF COMPLEMENT 



1. Heat 1 c.c. of the 1: 10 dilution of fresh rabbit immune serum used in the pre- 

 ceding experiment to 56 C. for half an hour (in a water-bath) . 



2. In a test-tube place a cubic centimeter of this heated serum and 1 c.c. of a 234 

 per cent, suspension of sheep cells and sufficient salt solution. Shake gently and 

 incubate for one hour. 



(a) Does hemolysis occur? 



(b) How do you explain the result? 



(c) What is meant by inactivation of complement? 



(d) Is complement thermostabile? 



3. Add to the tube 1 c.c. of fresh guinea-pig serum diluted 1:10 and reincubate 

 for an hour. 



(e) Has hemolysis occurred? 



(f) How do you explain the result? 



(g) What is meant by reinactivation? 



