146 THEORIES CONCERNING IMMUNITY 



sera for all the infectious diseases of which the bacteria were 

 known and could be cultivated (cholera, plague, typhoid 

 fever, tuberculosis, anthrax, and others). 



Horses and other animals were therefore injected, first 

 with sterilized cultures, then with attenuated and lastly 

 with virulent cultures of these bacilli, repeating these injec- 

 tions for weeks and months and increasing the doses. Rarely 

 was the desired result, that is, a really active serum, obtained. 

 The animals so treated became immune, it is true, never 

 suffered from plague or typhoid fever, but the subcutaneous 

 injections caused the formation of edemas, abscesses and 

 other lesions which complicated the treatment, while animals 

 into whose veins the injections were made often died on the 

 very instant or several minutes after the injection, They 

 fell as if knocked down, and died after a few convulsions. 

 It was, therefore, Arthus's local anaphylaxis or Richet's 

 anaphylactic shock which were in these instances caused 

 by bacterial injections, and which complicated the process 

 of immunization. 



In this way it was confirmed that living or dead pathogenic 

 bacteria, and in certain cases, also the filtered broth cultures 

 were able to cause in the organism the same reactions as 

 alimentary or toxic albumins. 



R/arely could this be observed in the practice of preventive 

 vaccinations because, in order to protect the organism 

 against spontaneous infection, in which the dose of infecting 

 bacilli is always very small, it was sufficient to inject one or 

 at the most two small vaccinating doses. The serum of an 

 animal so vaccinated had no curative power, and could not 

 cure actual disease; but it was reasonable to suppose that 

 by multiplying injections and by increasing the doses of the 

 vaccine, sera would be obtained similar in curative power to 

 antitoxic sera (diphtheria, tetanus). 



It was also thought that the anaphylactic complications 

 were the very obstacles to the formation of large quantities of 

 antibacterial products, and thus endeavors were made to 

 find a new weapon or circuitous road to overcome this obstacle 

 or to avoid it. But this attempt would perhaps not have 

 been undertaken with so much alacrity, had not the accidents 



