IMMUNIZATION~~AGAINST DIPHTHERIA. 105 



by the medical profession. Serum, however, has the advantage 

 of always being ready for use and not requiring sterilization 

 before administration. 



In some of the severer cases of nasal diphtheria, anti-toxin 

 has been sprayed^on the membrane with some beneficial results. 

 Frequently too, it is observed that diphtheria bacilli remains viable 

 in the nose and throat after an apparent recovery from the dis- 

 ease. Such persons frequently are the cause of the spread of 

 diphtheria. Various attempts have been made to remove the 

 diphtheria bacilli from the nose and throat of these apparently 

 well individuals. In ' addition to the antiseptic methods em- 

 ployed in the treatment of this condition, diphtheria anti-toxin 

 has been applied locally. Recently it has been proposed to ac- 

 tively immunize such individuals by the injection of bacterial 

 vaccines made from the cultures of diphtheria bacilli isolated 

 from the patient. 



Immunization of well individuals against possible diphtheria 

 infection has been practiced for some time. It has been quite 

 definitely proven that injection of a relatively small number of 

 anti-toxic units will protect from four to six weeks against in- 

 fection with the diphtheria bacillus. The doses generally recom- 

 mended are from three hundred to five hundred units in small 

 children and one thousand units for older children and adults. 

 While the custom concerning the immunization of well persons 

 varies, it is quite generally accepted that children who have been 

 exposed to diphtheria should receive at once immunizing doses of 

 diphtheria, while adults seldom are treated in this way. 



The definitely beneficial results which have been obtained 

 by the use of diphtheria anti-toxin in the treatment of diphtheria, 

 ought to be sufficient to convince the practitioner that diphtheria 

 anti-toxin should be used in practically all cases of diphtheria. 

 Moreover the practioner ought to know enough concerning the 

 symptoms and complications of diphtheria, and the untoward 

 effects of serum injection to distinguish the conditions dependent 

 upon the disease and those dependent upon the serum injected. 

 It is not unusual for the practioner to diagnose the transient serum 

 rashes as erysiplas, and the edema, following serum injections, 



