SE&UM THERAPY 123 



specific protein. The two actions may furthermore take 

 place simultaneously. 



Diphtheria and erysipelas are very instructive in this way. 

 Most, if not all, horses yield in the normal state antidiph- 

 theritic and antistreptococcus serum of very appreciable 

 potency (up to 50 antitoxic units per c.c. for diphtheria) and 

 although it is unlikely that horses which are naturally refrac- 

 tory for these two diseases could acquire this spontaneous 

 immunity, it is possible that the serum of normal horses acts 

 like a non-specific antigen and this is not surprising since we 

 know that carmin will neutralize tetanus toxin. In other 

 words, a biologically neutral and non-specific substance can 

 produce a reaction of the same nature as a specific antitoxin. 

 The differences are only in proportions and degrees. 



It would not be difficult to elaborate a program of studies 

 which would enable us to exactly differentiate the cases of 

 intoxication, due to the direct action of toxins, from cases of 

 anaphylaxis caused by bacterial albumins, or in other words, 

 the cases amenable to treatment by antisera from those in 

 which such a serum could do only harm. 



