A Chimæric Duck with the Head of a Chick

Abstract

IT is well known that the chick embryo fails to produce detectable antibodies against various foreign antigens, so providing a favourable environment for culturing viruses and transplanting various tissues of birds and mammals¹. It is also known from the work of Billingham et al.² that “actively acquired tolerance”, the power to react immunologically against foreign homologous tissue cells with which they have been inoculated in fœtal life, is never developed by birds and mammals, or developed only to a limited degree. A renewed interest in heterotransplantation stimulated us to graft various types of tissue primordia between embryos of two different genera of birds, the chick (Galliformes) and the duck (Anseres). Using the same combination, Hašek and his co-workers were not successful in inducing a tolerance for skin heterografts between young obtained by embryonic parabiosis³ or between young injected with each other's spleen or bone marrow cells shortly after hatching⁴. On the other hand, some cases of limb bud grafting during early days of incubation by Eastlick⁵ seem to indicate a certain degree of tolerance, although his experiment was carried out from a point of view of tissue incompatibility in heterologous combination⁶.