THE UNIQUENESS OF THE INDIVIDUAL 



other at Oak Ridge, have now shown that the latter explana- 

 tion is certainly correct. A heavily irradiated mouse is no 

 longer capable of resisting the transplantation of foreign, even 

 of remotely foreign, tissue; when it is injected with blood- 

 forming cells from bone marrow or other blood-forming centres 

 of normal mice, the cells establish themselves without opposi- 

 tion in their new surroundings, and the irradiated mouse 

 becomes a '"radiation chimera** in which the foreign blood- 

 forming tissues act proxy for its own. 



The injection of high doses of cortisone, a drug which is 

 closely related to one of the natural secretions of the cortex of 

 the adrenal gland, produces an effect which has something in 

 common with radiation sickness. Steroid hormones of the class 

 to which cortisone belongs have a powerfully inhibitory effect 

 upon the growth and activity of all lymphoidal tissue — upon, 

 therefore, the cells which undertake their owners' immuno- 

 logical reactions. The injection of large doses of cortisone can 

 certainly prolong the life of homografts, though (for reasons 

 which are still not quite fully explained) it does so more readily 

 in mice and rabbits than in guinea-pigs or human beings. At 

 one time we hoped that cortisone would be a useful minor 

 addition to the armoury of the plastic surgeon in the treatment 

 of very extensive burns. The great raw wounds left by deep and 

 widespread burns are still sometimes covered with homografts 

 of skin; homografts make a perfect temporary dressing which 

 may tide the patient over until he can afford to provide some 

 skin grafts of his own. It would buy useful time if these homo- 

 grafts were made to survive only twdce as long as could 

 otherwise be expected, and this is what we hoped that cortisone 

 would do. Unfortunately, it seems that cortisone could prolong 

 the life of homografts on human beings only at dosages which 

 would have secondary ill effects of a gravity which an already 

 sick patient could not put up with Yet the research account 

 is by no means all a matter of debit, for study of the action of 



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