detente progress. 



No. 13. March, 1895. Vol. III. 



ANTITOXIN. 



ONE of the earliest empiricisms with regard to com- 

 municable diseases affecting men and animals was 

 the knowledge that some do not affect certain species or 

 certain ages, and, further, that some, like smallpox, scarlet 

 fever, etc., attack an individual generally once only. 

 Medical science has for generations expressed these facts 

 in terms which are familiar to everybody, though their 

 exact nature remained unknown. The terms that were 

 and are still used in a technical sense for indicating that 

 a particular individual is not attackable by a particular 

 disease, are "lack of predisposition," " unsusceptibility," or 

 "immunity". This phraseology went further, and dis- 

 tinguished natural or congenital or spontaneous immunity 

 from "acquired immunity" ; the latter indicating that, owing 

 to having passed through one attack, the individual is now 

 possessed of immunity against the particular disease. But it 

 is obvious that these terms are merely paraphrases of condi- 

 tions that are patent to every one, and are no more or no better 

 understood whether used by laymen or in a technical sense. 

 After Pasteur showed that various fermentative changes, 

 such as the alcoholic fermentation, acetic acid fermentation, 

 the conversion of urea into ammonium carbonate, are due to 

 the activity of specific microbes — yeast cells, bacterium aceti, 

 or micrococcus ureae respectively — the infectious diseases 

 were likewise assumed to be comparable to specific fermen- 

 tative processes, caused in the infected body by the specific 

 microbes ; and, further, the nature of natural unsuscepti- 

 bility and acquired immunity began to be discussed. One 

 of the earliest theories concerning this subject took its basis 



