148 IMMUNE SERA 



observing the effect of cow-pox inoculation in 

 primary and subsequent vaccinations. The re- 

 vaccinated overcomes the whole process with a very 

 slight local reaction a few millimeters in size, while 

 the person vaccinated the first time shows extensive 

 local inflammation, fever, and other general symp- 

 toms. If the reaction is studied on the day follow- 

 ing the vaccination, we shall find that the re- 

 vaccinated is really hypersensitive, because at this 

 time the first vaccinated does not show any reaction, 

 while the revaccinated responds with a local inflam- 

 matory process. In tuberculosis, glanders, and 

 other infections the injection of extracts of the 

 infecting bacterium (tuberculin, mallein, etc.) pro- 

 duces characteristic local and general symptoms, 

 because of the specific hypersensitive condition 

 present in such infections. These reactions can 

 therefore be employed in the diagnosis of such in- 

 fections. The symptoms of hay fever, and of urti- 

 caria appear to be merely examples of proteid 

 hypersensi ti ven ess . 



Supposed Relation to Precipitin Action. 

 Attempts have also been made to associate the 

 phenomena of anaphylaxis with the action of pre- 

 cipitins. Hamburger and Moro were the first (1903) 

 who found that man forms precipitins after the 

 injection of horse serum. Precipitin was present 

 after the appearance of serum rashes ; therefore they 

 suggested a connection between serum exanthem 



