QUESTIONS 85 



(for example that of the horse) and passively by taking the serum 

 of the same guinea-pig, after two or three weeks, and injecting it 

 into another guinea-pig, producing in it the same anaphylaxis or 

 hypersusceptibility against the alien serum. 



Sudden Unexplained Loss in Antitoxic Value. Another occasional 

 peculiar occurrence difficult to explain with our present knowledge of 

 the details of the processes of immunity is the following: 



A horse may have been highly immunized (hyperimmunized) 

 against tetanus toxin. The blood serum of this horse shows an enor- 

 mous amount of antitoxin in other words, it shows in each cubic 

 centimeter a high figure of immunity units. The animal receives 

 another large dose of tetanus toxins. This ordinarily would cause 

 the antitoxic value of its serum to rise still higher, or, at least, if the 

 limit has been reached to remain stationary. Instead of this the 

 antitoxic value sinks enormously, the toxins are not properly neu- 

 tralized, and the horse gets very sick and may even die. There is 

 no satisfactory explanation for this peculiar occurrence which appar- 

 ently opposes all dicta of the theories of immunity. 



QUESTIONS. 



1. What is an antitoxin? What effect has it upon a toxin? 



2. How can this effect be demonstrated? 



3. What happens if we inject cholera spirilla into the peritoneal cavity of 

 an animal not very susceptible to them? 



4. What is an agglutinin? What is a lysin? 



5. What properties does a rabbit's blood serum acquire if we inject into this 

 animal human blood serum several times at intervals ? 



6. What is a precipitin ? Describe the procedure necessary to produce pre- 

 cipitins for horse's blood serum in the body of a rabbit. 



7. What practical use has been made of the precipitin test in forensic medicine ? 



8. Give a definition of the term antibodies. 



9. What is an antigen? 



10. What are the antibodies against tetanus and diphtheria toxins? How 

 prepared and obtained ? 



11. What is the paraenteral method of producing antibodies? 



12. What is meant by virulency; what by attenuation? How can virulent 

 bacteria or their toxins be attenuated ? 



13. What is meant by a vaccine? 



14. What is an immune serum? 



15. What is meant by the term immunity? 



16. What is congenital natural immunity? What is naturally acquired 

 immunity ? 



17. What is artificial immunity? What is the difference between active and 

 passive immunity ? 



18. What is the simultaneous method of immunizing an animal? Name 

 some diseases against which this method is used. 



19. What circumstances influence the union between toxin and antitoxin? 



20. What is the benzole ring of Kekule ? 



21. What does the term side-chain mean as used in organic chemistry? 



22. Explain the terms: haptophore, haptophile, toxophore, toxophile, side- 

 chains. 



23. Explain the interaction of these side-chains toward each other. 



24. What generally happens if tissue elements-are destroyed ? 



25. What is a cell receptor? 



26. What happens according to the side-chain theory if cell receptors are 

 destroyed ? 



