Published online by Cambridge University Press: 03 July 2018
According to Borst (1913) each individual should be regarded as a specific biochemical system, and within this common background the different organs and tissues work together whilst preserving their own characteristics. On such a foundation, strengthened by the results of his own extensive experiments, Loeb (1930,1945) has built up his conception of the biological basis of individuality. According to his thesis the individuality of a tissue is a summation and integration of qualities in respect of its identity as a particular tissue or organ, in respect of the organism of which it is a part, and in respect of the species and order of this organism. The autograft is attuned to the biochemical system of the organism and is therefore accepted as a transplant, but the host reacts to the homograft (and more so to the heterograft) and makes an effort to destroy it. While the extent of the host reaction depends on many factors—e.g. genetical relationship, age of host and donor, etc.—the ability of different organs and tissues to survive as homografts varies considerably. It is, for example, well known that homografts of cartilage and cornea survive within the host long after homografts of other tissues and organs have been destroyed.
To regard the more prolonged survival of homografts of cartilage and cornea as evidence of low tissue specificity (Loeb, 1930, 1945) still leaves undetermined the real reason why these particular tissues are less readily overwhelmed by those of the host.