HILARY KOPROWSKI 
RESISTANCE AND SUSCEPTIBILITY 
** Just as we don’t know what a spirit is, so we are ignorant of what 
a body is: we see some of its properties; but what is the subject in 
which these properties reside?”’ 
VOLTAIRE: Philosophical Dictionary 
These forays into the future of mankind would not be com- 
plete without a brief consideration of the problem of resistance 
and susceptibility of man to diseases. Although Swift was sure 
to recognize ‘‘who first brought the pox into a noble house 
which hath lineally descended in scrofulous tumours to their 
posterity”’, at present, unfortunately, we know next to nothing 
about the genetic factors which may determine susceptibility of 
man to a given infection. A fairly convincing case can be 
built up for the relative resistance to tuberculosis of Central 
European Jews, who after migration to Israel about twenty 
years ago ‘“‘mixed”’ with the Jewish population of North Africa 
and Asia Minor. The result of the contact was the appearance 
of a fulminant type of tuberculosis among the nomadic Jews, 
whereas the Central Europeans continued to suffer only from 
the mild variety of the disease. 
More precise data are currently available about a greater 
susceptibility to infection and malignancy among individuals 
suffering from several types of congenital abnormalities. For 
instance, the incidence of leukaemia (of congenital type) is 
twenty times higher in Mongols than in normal children. 
Mongols and subjects suffering from agammaglobulinaemia are 
easy prey to infections, as are individuals suffering from other 
types of congenitally acquired metabolic disorders. ‘These traits 
are, however, determined by sex-linked recessive genes and it 
is hoped they will not present any major problems for genera- 
tions to come. 
Whether there exists in the human population a trait which 
is inherited as a dominant character and which determines 
susceptibility or resistance to several major infections and 
cancer is unknown at present; moreover, it is difficult to deter- 
mine which method is to be chosen to make a rational approach 
to the study of this important problem. For instance, we would 
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