TETANUS 133 



repeated injection of gradually increasing doses of 

 tetanus toxin, until the blood contains the required 

 amount of antitoxin; the blood-serum of the immune 

 animal is capable of protecting the susceptible 

 animal or human from the action of the tetanus toxin 

 and also against the effects of the living tetanus 

 bacillus. 



The use of the tetanus antitoxin for the treatment 

 of tetanus has been far less successful than the use 

 of diphtheria antitoxin for diphtheria, because in 

 diphtheria the local signs in the throat lead to an 

 early diagnosis and treatment before the bacilli 

 have produced an overwhelming amount of toxin; 

 while in tetanus the first symptoms are the convul- 

 sions which are due to the presence of the toxins. 

 Also, the toxins of tetanus have an affinity for the 

 cells of the central nervous system, while the toxins 

 of diphtheria act upon the tissues of less vital im- 

 portance. 



The other pathogenic anaerobes are Bacillus 

 chauvei, the cause of a disease in cattle commonly 

 known as " black leg," "quarter evil," or "symptom- 

 atic anthrax"; the Bacillus edematus, which is the 

 cause of malignant edema; the Bacillus Welchii, or 

 gas-producing bacillus, found in cases of emphyse- 



