TWENTY-FIVE YEARS OF BACTERIOLOGY 125 



research and how rich the booty which accrued from those 

 labors tinged with the radiance of the real scientific 

 imagination of an Ehrlich, a MetchnikofT, and a Bor- 

 det. 



Not all the high expectations of practical benefit to fol- 

 low from these discoveries have been realized, but some- 

 times the very failures have been turned to account in 

 opening up new, or illuminating old, avenues of progress. 

 In this connection it is instructive to recall the early pro- 

 nouncement of Behring made two years after the discov- 

 ery of antitoxin, and while he was under the influence 

 doubtless of that great contribution: 



"The present state of the immunity question," he says, 

 "may be defined as follows : Thus far no generally ap- 

 plicable explanation for natural immunity has been forth- 

 coming. But of the artificially produced immunity it may 

 be said that the precise study of a number of examples 

 has so far advanced our knowledge that we may assert 

 with confidence that the immune state arises from a pecu- 

 liarity of the blood and, indeed, of its cell-free portion; 

 in no instance in which a sufficiently high grade of im- 

 munity has been attained in an animal species, easily sus- 

 ceptible to the infection in question, has the blood 

 withdrawn from the body failed to show evidences of the 

 presence of the immunity-conferring substances." 



In this statement will be perceived the extreme humoral 

 view of the origin of immunity, which subsequent inves- 

 tigators failed to uphold. But he continues in a prophetic 

 vein, unfortunately likewise destined not to be wholly 

 fulfilled. 



"With the achieving of this standpoint the next step 

 in the winning of specific curative agents for the infectious 

 diseases is clearly outlined: all that is required is the in- 

 duction in a susceptible animal species of a high degree 

 of artificial immunity, and then to test the blood for the 

 presence of protective and healing substances." 



Time has exposed the fallacy of this over-confident 



