In recent years greet advances have been made in the
understanding of the nature of the reaction of a host to
transplants of tissue of homogenous origin. In general,
such transplants fail because of the development of an
immune response by the host against the transplant. The
success of bone homografts in the light of this new knowledge
had been largely unexplained.
A. further study was, therefore, undertaken to determine
whether the apparently privileged behaviour of bone
homografts was due to a fundamental difference between bone
and other tissues with respect to homograft immunity. The
experimental work on this part of the study is described in
Chapters I and II of the thesis.
Chapter III of this thesis describes an attempt to
evaluate different bone grafting materials in order to assess their relative clinical value. In devising a biological test for a bone graft the author has tried to
eliminate some of the sources of uncertainty which had led
to the conflicting conclusions of previous workers. wrong
these had been the use of test situations which did not
correspond to any clinical bone grafting procedure; the use
of inexact methods for measuring a graft's ;progress; or the
evaluation of some aspect of a graft's behaviour which was
not relevant to its clinical function.
Many bone graft materials have been used clinically
or experimentally with apparent success as alternatives
Six of these materials which appeared to hold most promise were subjected to a comparative experimental study.
Frozen, freeze-dried and freeze-died irradiated homografts were found to behave more favourably than
autoclaved, demineralized and deproteinized homograft.
The type of bone bank recommended for clinical use depends on the needs of the area, a frozen bone bank being satisfactory for local use, while a freeze-dried bone bank
preferable where wider distribution is required.
Tonizing irradiation is the most satisfactory method
of sterilizing bone and may be used with either method of