THE UNIQUENESS OF THE INDIVIDUAL 



their benefactions might appear to be) that immunology is now 

 hardly less commodious than psychology in providing an 

 etiological funkhole for diseases of which the physical causes 

 are still unknown. That most immunological reactions do good 

 is of course a truism, though it is a truism Avhose truth has been 

 formally proved only in very recent years. There exists a con- 

 genital affliction, agammaglobulinaemia, the victims of which 

 are unable or almost unable to manufacture blood protein of 

 the class, gamma globulins, to which most antibodies belong. 

 Being virtually unable to manufacture antibodies, sufferers 

 from agammaglobulinaemia go down with almost every in- 

 fectious disease they may be exposed to, and perhaps with the 

 same disease again and again. Only antibiotics can keep them 

 alive, to be witnesses to the truth that, under normal circum- 

 stances, immunological reactions are necessary not merely for 

 remaining in health but for remaining alive at all. The recog- 

 nition of the disease in its severest form had therefore to await 

 the discovery of antibiotics. The victims of agammaglobulin- 

 aemia can be successfully grafted with foreign skin,^ and this 

 has raised hopes that they might be surgically endowed with 

 cells capable of manufacturing antibodies. 



But, it may be objected, how can we be certain that trans- 

 plantation immunity is not a blessing in disguise — that it is 

 not deeply harmful to mix up tissues of different genetic origins 

 in a single individual, the very thing which transplantation im- 

 munity normally makes it impossible to do? A few years ago this 

 argument or innuendo might have carried weight, but now it is 

 no longer tenable. Chimeras occur naturally or, as I shall explain 

 later, can be made artificially. Compared with ordinary animals, 

 chimeras are at no disadvantage; or, if they are at a disad- 

 vantage (I am thinking of ''freemartinism'', the sterility of most 

 female members of twin pairs of unlike sex in cattle), it is for 

 reasons unconnected with chimerism as such. There is therefore 



1 11. A. Good and R. L. Varco, /. American Med. Assoc. ^ 157, p. 713, 1955. 



153 



