216 DISCOVERY CH. 



disease which can be treated with the greatest confidence 

 of success. Formerly the medical man standing at the 

 bedside of a child struggling for breath was almost 

 helpless to relieve its anguish except by a dangerous 

 operation ; now he has at his disposal a remedy which, 

 if used quickly enough, extinguishes the disease as surely 

 as water does a raging fire. He used to fight in the 

 dark against an unknown foe, but he now knows the 

 nature of the forces against him, and has a weapon which 

 will vanquish them completely. 



It is scarcely too much to say that of all the infective 

 diseases which trouble mankind, diphtheria stands 

 foremost as the one concerning which our knowledge is 

 the most complete ; and in this knowledge lies the 

 physician's power. The isolation of the specific microbe 

 which causes the disease was accomplished by Loefner in 

 1884. When this virulent bacillus is grown in broth, ifc 

 produces a quantity of a toxin which can be obtained in 

 the form of a clear liquid. Upon injecting the liquid into 

 a horse several times over a period of two or three months, 

 the horse's blood acquires a quality which counteracts its 

 effects ; and the serum obtained from the blood of such 

 an inoculated animal is the basis of the anti-toxin of 

 diphtheria upon which every doctor now depends for 

 the treatment of the disease. It was Behring who first 

 enunciated the principles of toxin and anti-toxin in 

 diseases, and to the studies of Roux we owe the pre- 

 paration of anti-diphtherial serum. 



The result of the use of the serum has been marvellous. 

 In pre-anti-toxin days, one child of every three infected 

 by the disease ended its sufferings in death ; now only 

 one diphtheria case in ten proves fatal, and when the 

 anti-toxin is used on the first day of the disease not more 

 than two or three cases in a hundred succumb to its 



