TEST TUBE AND BODY EXPERIMENTS. 



With regard to diphtheria: The degree of 



affinity between toxin and antitoxin iS' much ^. , , . 

 •' . Diphtheria 



stronger in this disease than is the affinity Antitoxin 

 between tetanus toxin and its antitoxin. Com- ' ^' 



plete neutralization in the test tube takes place 

 in fifteen minutes. Chemical tests have dem- 

 onstrated that the affinity of diphtheria toxin 

 for tissue cells is not nearly so great as is that 

 of tetanus. Diphtheria has been cured by the 

 toxin treatment on the second day, while cures 

 effected in tetanus cases are to say the least not 

 common. The toxin of diphtheria may affect 

 the nervous system and cause paralysis, but 

 this condition in diptheria does not often prove 

 fatal. Chemical experiments have shown that 

 the toxin of this disease is so situated in the 

 body as to be easy of access for the antitoxin. 



I. IMPORTANT POINTS TO BE REMEMBERED. 



in Serum Therapy are : 



(i.) Strength of the antitoxin injected. 



(2.) Freedom from bacteria and other 

 contamination. 



(3.) Time of administration, (early in the 



case). 



(4.) Quantity injected. 



(5.) Degree of affinity between toxin and 



antitoxin. 



179 



