244 BACILLUS DIPHTHERIA. 



theria contains a substance which neutralizes the effects of the 

 diphtheria bacillus and its toxin. Intensely virulent bacilli 

 are grown in alkaline bouillon in the incubator for five to 

 seven days until the medium is strongly alkaline. A 0.4 per 

 cent, solution of trikresol is then added and the mixture filt- 

 ered through porcelain. The filtrate contains the toxin, 

 which is used for immunizing purposes. 



One attack of diphtheria confers immunity, which is, how- 

 ever, of only temporary duration. If it is desired to immun- 

 ize persons who have been exposed to the disease, only a 

 small amount of the antitoxin is injected. Five hundred 

 units will confer protective immunity for about six weeks. 

 This injection should be made as promptly as possible, as it 

 will otherwise fail of producing the desired result. For 

 therapeutic purposes a larger amount that is, a stronger 

 serum must be used. 



The antitoxin treatment of diphtheria is an absolute specific, 

 and when used properly never fails to give the results which 

 are claimed for it. Notwithstanding the opinion of those who 

 are still prejudiced against it, the antitoxin should be used in 

 every case of diphtheria. Its use is never followed by 

 untoward results. The reported results which ostensibly 

 contraindicate the use of antitoxin are entirely due to faulty 

 administration and to its being used too late. It may be 

 well to refer briefly to its correct use. 



Use of antitoxin : Most important of all is that it should 

 be used early ; and, second, in sufficient strength. Although 

 only a short time is required for making a bacteriologic diag- 

 nosis, it is better, in order to be on the safe side, to use the 

 serum at once if diphtheria is suspected. Even if the micro- 

 scopic diagnosis negatives diphtheria, the injection of serum 

 will not have done any harm. The most common mistake 

 made in using the serum is in waiting until the medicinal 

 treatment has failed before the serum injection is made. Too 

 many practitioners look upon antitoxin as a last resort, and 

 when used as such it proves ineffectual. In severe cases of 

 diphtheria death usually results ; but if the serum has been 

 used, it is sure to be blamed for the fatal outcome. Perhaps the 

 case would have been saved if the serum had been used in time. 



