“…In none of these nine guinea-pigs were anaphylactic symptoms observed, and Weil stated that "for sensitization to occur an interval of time must elapse between the two injections". On the other hand, Friedemann (1909) had killed guinea-pigs by intravenous injections of mixtures of antiserum and antigen which had been incubated for a short period. After Friedemann's paper was published much work was done and many papers written on the supposed production of a poisonous substance (sometimes called anaphylatoxin) by the interaction of antigen and antibody.…”