ANTIBODIES 501 



Antibodies. There are many protective substances produced 

 in the blood in response to the entrance of disease germs or their 

 poisons. These substances are known as antibodies. Both 

 toxins and antibodies are specific for each disease. The toxin 

 produced by a typhoid bacillus will cause only typhoid and will 

 never cause diphtheria or any other disease, and the anti- 

 toxin made by the body to fight diphtheria will have no effect 

 on any other disease but diphtheria. This is true of all anti- 

 bodies. Antitoxin is one type of antibody produced in the blood 

 for the neutralizing of exotoxins. There may be antitoxins in 

 the blood for diphtheria, others for scarlet fever, and still others 

 for tetanus. The antitoxins neutralize the toxins produced by 

 the bacteria and at the same time the phagocytes destroy the 

 actual bacteria. 



Other protective bodies called lysins are present in normal 

 blood, which actually dissolve the bacteria. The lysins which 

 dissolve the bacteria are known as bacteriolvsins. There are 

 specific bacteriolysins produced to dissolve diphtheria germs. 

 Others dissolve typhoid bacilli and still others dissolve meningitis 

 germs. There are other kinds of lysins besides bacteriolysins. 

 One kind ma}^ dissolve foreign red blood corpuscles and is called 

 hemolysins. In blood transfusions, if one group of blood is intro- 

 duced into another group of blood, the hemolysins of the first blood 

 may dissolve the corpuscles of the second type. Therefore, trans- 

 fusions are made only among bloods belonging to similar groups. 



Certain protective substances are produced in blood to assist 

 the white corpuscles. For exampFe, agglutinins cause the germs 

 to stop moving and to gather in clusters or clumps. Then the 

 phagocytes and lysins can destroy them more quickly. Agglu- 

 tinins are produced in the body in combating typhoid. 



There are also precipitiris known to the biologist. Their action 

 is similar to that of agglutinins. They are specific for different types 

 of foreign proteins, bacterial and otherwise. Precipitins harden 



