LAST DAYS 239 



increasing doses of diphtheria toxin into a horse, 

 the blood of the animal comes, after a time, to con- 

 tain a quantity of antitoxins. After this occurs, 

 some of the blood of the horse is withdrawn, the 

 serum is extracted and preserved in vials with a 

 small amount of antiseptic. It is then ready to use 

 for cases of diphtheria. 



The gratifying results of the use of diphtheria 

 toxin are well known. If given early in the course 

 of the disease, it effects a cure in a very high per- 

 centage of cases, and the mortality of all cases 

 treated with antitoxin, as compared with the mor- 

 tality of untreated cases, is relatively low. Diph- 

 theria is a treacherous disease; it sometimes 

 snatches away its victims before the nature of the 

 malady is determined. Highly contagious and 

 often carried by persons not themselves affected, it 

 is remarkably persistent and still ranks among the 

 principal causes of death in the period of child- 

 hood. The work of Roux on diphtheria antitoxin 

 was suggested by some of the earlier experiments 

 of Pasteur on chicken cholera. Pasteur found 

 that the liquid obtained by filtering a culture of 

 the bacteria of chicken cholera would produce 

 some of the symptoms of this disease if injected 

 into a healthy fowl. He did not follow up the line 



