Every new laboratory method requires confirmation from many workers before being accepted as an established aid to investigation. The Wassermann syphilis reaction seems now to have reached a stage where it can be used as an actual laboratory aid in diagnosis; and, therefore, as it has been but sparingly commented on in American journals, a brief account of its significance will not come amiss.
To make this reaction plain to every physician we begin with the main fact to be remembered, namely that all such biologic experiments are physicochemical in their essential nature. This does not imply, however, that the technic is as easy as an ordinary chemical experiment. In order that the reaction may be understood, moreover, certain terms must be made clear.
An antibody is the reaction product formed in the blood of an animal when a solution of some substance, toxic or otherwise, is injected