608 Introduction to the Study of Science 



a potency or purity below the standard, or the wrong kind and 

 amount of preservative, the manufacturer must at once with- 

 draw that lot from the market. Thus a standard product is 

 insured which can be used with safety and give dependable 

 results. 



SUMMARY 



Edward Jenner, in 1796, improved the method of vaccination against 

 smallpox by using the virus or pus from cattle afflicted with cowpox. 



The discoveries of Pasteur revolutionized preventive medical 

 practice and initiated the use of inoculation in the treatment of rabies 

 and anthrax. 



Vaccines are used to immunize man against smallpox, typhoid 

 fever, cholera, and bubonic plague. 



Antitoxins are used to cure and give passive immunity to diphtheria 

 and tetanus. 



The production of antitoxins, as for diphtheria, is a process requir- 

 ing extreme care to insure a pure serum of known potency. N 



REVIEW QUESTIONS 



1. (a) What was the common method of preventing smallpox 

 before 1796? (6) What change in the method was made by Edward 

 Jenner? 2. What is the difference between vaccines and antitoxins? 

 3. How are the purity, potency, and safety of vaccines and antitoxins 

 insured? 4. Describe the preparation of diphtheria antitoxin. 

 5. What department of the Federal government supervises and tests 

 the products? 



SUGGESTIVE QUESTIONS 



1. Show that the sun is the source of your energy. 2. It has 

 been said that the total weight of microorganisms is greater than the 

 total weight of the animals of the earth. Show that the estimate is 

 a fair one. 3. Would you destroy, if you could, all bacteria for the 

 sake of getting rid of the pathogenic kinds? Would you destroy all 

 fungi if you could? Would you destroy the insects of the .prder 

 Diptera? Give reasons for your answers. 4. Which do you think 

 are more dangerous, insects or snakes? 5. In most cities ordinances 

 provide for fines and imprisonment for spitting in public places. Should 

 this ordinance be enforced? Does its enforcement interfere with 

 personal liberty? 



6. The average length of life of man in civilized countries is increas- 



