Summary and Conclusions
It has been shown that antibodies of three different types and contained in foreign or homologous serum appear in the blood stream but slowly and in slight degree after intratracheal injection. Conversely, such antibodies are retained in the lungs over a relatively prolonged period. These facts suggest that the lungs are only slightly permeable to antibody. Additional evidence indicated that the presence of sterile pulmonary inflammation exerted little effect on this permeability. On these grounds it was found impossible to agree with Besredka that the intratracheal route is a good way to induce general passive immunity.