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January 20, 1917


Author Affiliations


From the Department of Experimental Medicine, University of Illinois.

JAMA. 1917;LXVIII(3):159-161. doi:10.1001/jama.1917.04270010159001

A discussion of the possibilities and limitations of any topic involves more or less prediction. In science it is dangerous to predict and especially is this so just now concerning the subject at hand, because we are in the midst of a revolution in methods and in interpretations as applied to this field. It is with reluctance, therefore, that I attempt to present this subject, because I feel it cannot be done adequately at this time.

After an attack of many infectious and contagious diseases, such as typhoid fever, smallpox, measles, scarlet fever, the body becomes for a long time highly resistant to the given disease, but not to any other disease. The conception of specificity is here clear and definite.

Many years ago Jenner found that smallpox in the modified and relatively harmless form of cowpox could be given to human beings and that they were then almost as