BACTERIOLYSIS CYTOTOXINS 863 



ground slide or in a small tubule. Aspirate the mixture into the middle portion of 

 the stem and seal the pipet in a flame. Label with the final dilution (1: 128). 



4. Proceed in the same manner with the remaining five dilutions of the patient's 

 serum, which then, mixed with an equal quantity of culture, equals 1 : 64, 1 : 32, 1 : 16, 

 1 : 8, and 1 : 4. Place these pipets in a large test-tube and label with the patient's 

 name and time when placed in the incubator. 



5. Prepare a similar set of pipets using the control serum. 



6. Prepare a culture control by mixing equal volumes of culture and sterile broth. 



7. Place all pipets in the incubator at 37 C. for two hours. 



8. Prepare hanging-drop preparations of each pipet by breaking off the tip and 

 placing a drop of the contents (after mixing) on a cover slide and suspending in the 

 usual manner. First examine the culture control and then each of the various dilu- 

 tions, noting in each case the dilution in which there is the first bacteriolytic effect, 

 and the dilution in which there is a complete effect; arrive at the bacteriolytic index 

 by comparing the patient's and the control blood just as the opsonic index is stated. 



(a) What are the first evidences of bacteriolysis? 



(b) Are endotoxins neutralized when bacteriolysis occurs? 



EXERCISE 51. BACTERIOLYSIS 



EXPERIMENT 103. METHOD OF MEASURING THE BACTERICIDAL AC- 

 TIVITY OF THE BLOOD IN VITRO (METHOD OF STERN AND KORTE) 



With a culture of typhoid bacilli, rabbit typhoid immune serum, and rabbit 

 complement serum, a test may be carried out after the method given hi the text. 



(a) What main precautions are to be followed in this method? 



(b) Discuss complement deviation. 



(c) Discuss the practical value of this method. 



EXERCISE 52. CYTOTOXINS 

 EXPERIMENT 104. ACTION OF NEPHROTOXIN 



1. Prepare an emulsion of dog kidney as described on page 73 and immunize 

 a rabbit. 



2. Inject a dog intravenously with 2 c.c. of rabbit immune serum per kilo of body 

 weight. 



3. Place the animal in a metabolism cage, collect all urine, and carefully examine 

 for albumin, casts, and hemoglobin; make quantitative albumin determinations. 



4. After three days autopsy and examine the kidneys and liver histologically. 



5. Heat the immune serum to 56 C. for thirty minutes and place increasing 

 amounts in a series of test-tubes as follows: 0.01, 0.05, 0.08, 0.1, and 0.2 c.c.; add 

 1 c.c. of fresh guinea-pig complement serum 1 : 20, and 1 c.c. of 2^ per cent, suspension 

 of washed dog erythrocytes. Incubate for two hours. 



(a) Describe the changes occurring in the liver and kidneys. Give 

 the prevailing views regarding the mechanism of their production. 



(b) Are there any evidences of a hemolytic action of the serum in 

 vivo? In 



