462 INFECTION AND RESISTANCE 



the case of children during the ages at which they are most suscep- 

 tible to the disease, the prolonged immunity resulting from the treat- 

 ment should strongly recommend it as a method of promise for the 

 gradual eradication of epidemics. Behring also suggests it as a 

 hopeful method of treatment in the case of bacillus carriers. 



Schreiber and others have reported upon the effects of treatment 

 when carried out with Behring's mixtures. In the earlier experi- 

 ments of Hahn, mixtures were used in which there was a slight excess 

 of toxin. The later experiments were made with mixtures which 

 were completely neutralized for guinea pigs. In Schreiber's cases 

 from two to six injections were made at intervals of three to five 

 days, most of them subcutaneously, and some of them intramuscu- 

 larly. In no case were there serious reactions, although occasionally 

 there were slight swelling of regional lymph nodes and a little fever. 

 The effects of immunization were noticeable about 23 to 25 days 

 later. When two injections only had been made, at least 0.075 of an 

 antitoxin unit to the cubic centimeter was present. The highest value 

 obtained after two injections was one unit to one cubic centimeter. 

 In nine patients who had been treated by four to seven injections 

 with gradually increasing doses, as much as 10 to 75 antitoxin units 

 to the cubic centimeter resulted. It appears, therefore, that in med- 

 ical practice this method is safe, and that with as little as two injec- 

 tions antitoxin values may be obtained which entirely suffice for the 

 protection of human beings against the ordinary dangers of diph- 

 theria infection, an immunity which, as far as we can judge at 

 present, may last about two years. 



Another advantage which Behring claims for his method is the 

 production of homologous antitoxin in human beings for the passive 

 immunization of other human beings. Mathes has tried this in 

 children with the idea of thereby avoiding the dangers of anaphy- 

 laxis. Incidentally it was claimed in this case that the passive im- 

 munization, when carried out with homologous serum, lasted longer 

 than did that conferred by horse serum. However, one case is 

 hardly enough to establish such a fact. 



THE INTRACUTANEOUS METHOD OF DETERMINING TOXIN AND 

 ANTITOXIN VALUES 



Marks 29 was the first to utilize the prevention of local edema or 

 injury for the determination of antitoxin values. He mixed diph- 

 theria antitoxin and toxin and injected them subcutaneously into 

 guinea pigs, claiming that this method was considerably more deli- 

 cate than the Ehrlich method, since the amount of toxin capable of 

 causing localized edema amounted to as little as one-twentieth of a 



29 Marks. Centralbl. f. Bakt., Orig. Vol. 36. 



