THE UNIQUENESS OF THE INDIVIDUAL 



is between treatments which are non-specific and treatments 

 which are specific in their action. By a non-specific treatment 

 I mean a treatment which will weaken, or under extreme 

 circumstances abolish, the reaction against homografts from 

 all sources — and, for full measure, probably abolish most other 

 immunological responses as well. A specific treatment is one 

 which weakens the reaction against homografts from some one 

 particular donor, or from the members of some one highly 

 inbred strain, without prejudice to the reaction against homo- 

 grafts from other sources or, a fortiori, to the recation against 

 antigens of other quite different kinds. 



I shall mention only two of the non-specific treatments: 

 X-irradiation, and the injection of cortisone; and I mention 

 X-iriadiation not because it is useful in the surgery of trans- 

 plantation but simply because it has the awful prestige of 

 anything to do with the threat of atomic war. ''Whole body 

 irradiation"* of a sufficient dosage — for a mouse, something less 

 than one thousand Roentgen units — causes, amongst other 

 things, complete immunological prostration and severe and 

 usually irreparable damage to blood-forming cells. It was dis- 

 covered in America that mice which had received a dosage of 

 radiation which would otherwise have been rapidly fatal could 

 be kept alive by injecting them with cellular pulps made from 

 the blood-forming tissues of other mice or even of members of 

 alien species. For many years the nature of the protective agent 

 contained within this pulp remained in doubt; some main- 

 tained that it was humoral in nature, and that it could exist 

 apart from living cells, others that the injection of the pulp was 

 in effect a transplantation of normal living cells which simply 

 took the place of those damaged or destroyed by radiation. 

 Two independent groups of scientists,^ one at Harwell and the 



^ C. E. Ford, J. L. Hamerton, D. W. H. Barnes and J. F. Loutit, Nature, 

 177, p. 452, 1956; D. L. Lindsley, T. T. Odell and F. G. Tausche, Proc. Soc. 

 exp. Biol. Med., 90, p. 512, 1955. 



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