80 MODERN BIOLOGIC THERAPEUSIS 



of diphtheria of not less than 50 per cent and, 

 under the most favorable conditions, a reduc- 

 tion to one-quarter or even less of the previous 

 death rate. This has occurred not in one city 

 at one particular time but in many cities and 

 different countries at different seasons of the 

 year, and always in conjunction with the intro- 

 duction of antitoxic serum and proportionate 

 to the extent of its use." 



PROPHYLAXIS 



When children or adults have been exposed 

 to diphtheria they may be protected from the 

 disease by the administration of 1,000 units of 

 Diphtheria Antitoxin. This is now the ac- 

 cepted prophylactic dose. The protection is 

 absolute for ten days and usually lasts from 

 three to four weeks. If danger of infection 

 persists longer than two \veeks the prophylac- 

 tic injection may be repeated, inasmuch as an- 

 titoxic serum consists of foreign protein and 

 is eliminated from the system rather rapidly. 

 Hence, for prophylactic purposes, it is desir- 

 able that the serum be administered subcuta- 

 neously preferably in the interscapular re- 

 gion so that it will be absorbed slowly and its 



