COMPLEMENT FIXATION IN THE DIFFERENTIATION OF PROTEINS 937 



(b) Is complement fixation in bacterial infections likely to be as well 

 marked as in syphilis? 



(c) In what cases of gonococcus infection is the reaction 'likely to be 

 negative? Likely to be positive? 



(d) How soon after infection is the reaction likely to become posi- 

 tive? 



(e) Discuss the practical value of the gonococcus complement-fixation 

 test. 



EXERCISE 45. GONOCOCCUS COMPLEMENT-FIXATION TEST 

 EXPERIMENT 98. TECHNIC OF THE GONOCOCCUS REACTION 



1. Using a similar set of serums as in the preceding experiment, conduct the 

 reactions with the one-tenth technic as described on page 508. 



(a) What is the main advantage of this technic? 



(b) By which method are the reactions more easily read and re- 

 corded? 



EXERCISE 46. COMPLEMENT FIXATION IN THE DIFFERENTIATION OF 



PROTEINS 



EXPERIMENT 99. TITRATION OF IMMUNE SERUMS 



1. Secure 1 c.c. each of antihuman and antihorse serum. Inactivate both. 



2. Secure 0.1 c.c. each of fresh human and horse serum and dilute 1: 1000. 



3. Conduct an antigenic titration of each immune serum as described on page 528. 



(a) Explain the mechanism of this reaction. 



(b) Are protein amboceptors specific? 



(c) Discuss the question of inhibition of hemolysis due to a precipitin 

 reaction. 



EXERCISE 47. COMPLEMENT FIXATION IN THE DIFFERENTIATION OF 



PROTEINS 



EXPERIMENT 100. TECHNIC OF THE FORENSIC BLOOD TEST 



1. Secure from the instructor two pieces of gauze stained respectively with human 

 and horse blood. These are to be numbered and their identity known only to in- 

 structor. 



2. Secure 1 c.c. each of antihuman and antihorse serum. 



3. Secure 0.1 c.c. of known human and horse serum for controls. 



4. Proceed with the test for identifying these bloods as described on page 527. 



(a) Discuss the specificity of this test. 



(b) Is this test more delicate than the precipitin reaction? 



