The strange case of the spotted mice
'Can the leopard change his spots?' the prophet asked ( Jeremiah, 13:23), clearly not expecting to be told he can. Nor, indeed, can mice, except under the rather discreditable circumstances now to be outlined.
It is a well-attested truth of observation that except under special and unusual circumstances skin from one mouse or human being will not form a permanent graft after transplantation to another mouse or another human being; for although such a graft heals into place it soon becomes inflamed and ulcerated, and eventually dries up and sloughs off. The exceptional circumstances are: in human beings, when donor and recipient are identical twins, and in mice when prolonged inbreeding (e.g., upward of twenty successive generations of brother/sister mating) has made the mice so closely similar to each other genetically that they almost could be identical twins.
This being so, great surprise was caused in the world of transplantation when Dr William Summerlin, a member of the largest and in many ways the most important cancer research centre in the world, the Sloan-Kettering Institute in New York, with the backing of his chief, Dr Robert A. Good, made known in 1973 his surprising claim that a comparatively simple procedure -- 'tissueculture' -- could make a skin graft or a corneal graft from a member of the same or even of a different species acceptable to an organism that would otherwise have rejected it. This claim was specially important because grafting skin from one human being to another has never entered clinical practice, in spite of encour-