248 CIVIC BIOLOGY 



The Avliitc corpuscles may not be able to ingest some bac- 

 teria unless there are certain substances in the blood to help 

 them. These are called opsonins (Gr. o-i/roji^eo), I prepare food 

 for), and their amount in the blood as compared with a nor- 

 mal standard is known as the opsonic index. The injection of 

 killed bacteria of the exact kind that are causiJig the trouble 

 (made with cultures taken from the patient — autogenous 

 bacterins) often results in a sharp rise in the opsonic index 

 and with this a quick defeat of the invading germs. 



Great prejudice has existed against the use of these vac- 

 cines, antitoxhis, bacterins, and serums, and one accident 

 attributed to them, perhaps falsely, is often made to out- 

 weigh in popular prejudice the literally thousands of deaths 

 caused by the natural course of infections. Beginning with 

 vaccination, discovered by Jenner, in 1796, we now have 

 safe and effective vaccines, antitoxins, bacterins, and serums 

 for rabies, diphtheria, tetanus (lockjaw), pneumonia, boils, 

 pimples, and inflammatory fevers, cholera, bubonic plague, 

 bacterial dysentery, cerebrospinal meningitis, and typhoid 

 fever, and, among animal diseases, anthrax, distemper of 

 (logs, hog and fowl choleras, blackleg, and tetanus, with 

 many more that are on the way toward perfection. It is 

 claimed by some high in authority that the present great war 

 \\'ill result in lengthening the average of human life by as 

 much as fifteen years, by breaking down apathy and ancient 

 prejudice aud demonstrating the value of modern bacterio- 

 logical science. Typhoid has been banished from our army 

 by preventive inoculation. Let some pupil volunteer to look 

 up the story of this and report to the class. 



Asepsis, antisepsis, germicides, and paths of entrance to the 

 body. Blood wells from a wound, carrying out the germs 

 that may have entered, rendering it germ-free, or aseptic, and 

 then it clots to seal it over. This is nature's primitive aseptic 

 surgery. The saliva is somewhat antiseptic, and the acid 



