“The term antibody today refers to discrete biochemical entities present in the blood. The belief that antibodies are such entities is held not only by scientists and physicians, but also by the lay public, who learns about “antibodies,” if not in school, then at least in the course of routine medical practices such as vaccination and, increasingly, through the so-called popularization of science. In addition, some people will readily associate the term antibody with the characteristic Y-shaped structure found not only in textbooks and specialized scientific articles but also, more recently, in advertisements and even as the logos of pharmaceutical and biotechnology companies.”