SERUM THERAPY 83 



the first twenty-four hours with membrane 

 limited to one tonsil, 5,000 units may suffice. 

 Cases with membrane extending to the soft pal- 

 ate and uvula, or to the posterior wall of the 

 pharynx, should always receive 10,000 units 

 as an initial dose. If, in addition, the nose or 

 naso-pharynx is involved, at least 15,000 to 

 20,000 units should be administered. If there 

 is a considerable amount of membrane, or if 

 the infection is a virulent one, or if the pro- 

 gress of the disease has been rapid, and partic- 

 ularly in all cases of laryngeal diphtheria 

 (croup), it is probably best to employ 20,000 to 

 25,000 units. 



Value of Large Doses The object of giving 

 large doses of antitoxin is to secure the rapid 

 and complete neutralization of the toxin by a 

 single dose of antitoxin. The endeavor should 

 be made to give at once, as an initial dose, such 

 an amount of antitoxin that this neutralization 

 will be accomplished without delay, and to in- 

 sure there being an excess of antitoxin still in 

 the system to combat toxins later elaborated. 

 To give a dose too small invites disaster by 

 causing delay in checking the diseased process. 

 To give too large a dose can do no harm and 



