936 EXPERIMENTAL INFECTION AND IMMUNITY 



(d) Does an active serum react more delicately than an inactivated 

 one? 



(e) In performing this test with unheated serum what precautions 

 are to be observed? 



EXERCISE 42. WASSERMANN AND NOGUCHI REACTIONS 

 EXPERIMENT 95. COMPARISON OF METHODS 



1. Secure five serums and a cerebrospinal fluid. 



2. Conduct a Wassermann reaction with each after the second method. 



3. Conduct a Noguchi test with each serum inactivated and using an extract of 

 acetone-insoluble lipoids. 



(a) How do the results compare? 



(b) Which reactions are more easily read? 



(c) Discuss the relative delicacy and value of the Wassermann and 

 Noguchi reactions with both active and inactivated serum in the latter. 



EXERCISE 43, GONOCOCCUS COMPLEMENT-FIXATION REACTION 

 EXPERIMENT 96. TITRATION OF GONOCOCCUS ANTIGEN 



1. Secure 1 c.c. of gonococcus antigen and dilute 1:10 by adding 9 c.c. normal 

 saline solution. 



2. Secure 1 c.c. of an antigonococcus serum or the serum of a person who reacts 

 positively and inactivate. 



3. Conduct an anticomplementary and antigenic titration as described on page 

 506. 



4. A similar titration may be conducted with glanders antigen and antiserum. 



(a) Give three methods of preparing a bacterial antigen. 



(b) Is it advisable to make polyvalent antigens and whjr? 



(c) Which is of more practical value, the anticomplementary or anti- 

 genic titration and why? 



(d) What part of the anticomplementary dose of an antigen may be 

 safely used in a diagnostic test? 



(e) Is it advisable to titrate a bacterial antigen at frequent intervals? 



EXERCISE 44. GONOCOCCUS COMPLEMENT-FIXATION REACTION 

 EXPERIMENT 97. TECHNIC OF THE GONOCOCCUS REACTION 



1. Secure six specimens of serum from a genito-urinary clinic, particularly of 

 men suffering with chronic gonococcus infections. Also a known positive and a 

 known normal serum for controls. 



2. Conduct the reactions after the method described on page 504. 



(a) Is the gonococcus reaction specific? 



