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131   DDT: Boon Or Bane?
      The Washington Post, January 4, 1969

     The Nobel Prize in medicine for 1948 was awarded to the Swiss
chemist Paul H. Mueller for his discovery of the remarkable new
insecticide dichloro-diphenyl-trichloromethylmethane, or DDT.

     Few scientific discoveries have been applied so quickly for
large-scale humanitarian benefit as DDT, whose insecticidal potency
was first reported in 1940.

     The Nobel Prize citation recounted that in October of 1943, a
heavy outbreak of typhus occurred in Naples.  When customary relief
measures proved inadequate, DDT treatment was introduced (for the
eradication of typhus-bearing lice).  In January, 1944, 1.3 million
people were treated, the citation noted, "and in a period of three
weeks the typhus epidemic was completely mastered.  Thus for the first
time in history a typhus outbreak was brought under control in
winter".

     After World War II, DDT was deployed worldwide as one of the main
weapons against malarial mosquitos and many other disease-bearing
insects.  It has unquestionably saved many millions of human lives
and brought many more out of the deadly lethargy of chronic
pestilence.  DDT has also played a vital part in the protection of
food crops against insect attack.

     At the occasion of his prize award, Dr. Mueller took pains to
point out that we did not sufficiently understand the biological
action of DDT on insects, and by implication the scope of potential
side effects on other species of animals and on man.  Two decades
later we still suffer from having only a fragmentary understanding
of its basic effects on cells.  But we are beginning to realize
that DDT is a two-edged sword whose long-term dangers may even rival 
its unarguable human benefits during and since World War II.

     DDT has a remarkable capacity to persist in the environment, its
residues passing from soil to insects to birds and fish and the
animals that eat them.  The chemical's persistence is a positive
advantage in crude public health work -- a few applications a year
can hold down the mosquito production of a malarial swamp.  But DDT
has been accumulating in the terrestrial environment to the point that
significant traces can be found in Antarctic birds, thousands of miles
away from the original sources of application.  DDT can be called the
first qualitatively new compound to be spread throughout the world by
human activity.

     In some wild species of birds, DDT has accumulated in body
tissues to the point of causing serious disturbances in the
metabolism of sex hormones.  These are manifested by a serious
thinning of the calcium carbonate shells of the birds' eggs and
interference in breeding.  Many biologists now warn that several
species of birds of prey, notably the peregrine falcon, are in danger
or early extinction.

     Man comes first, we may say, but we must at least perceive the
lesson of how we may be fouling our own next.  The falcon may be
doomed, and we may not be able to afford to give up DDT for its more
crucial life-preserving applications.  At the very least, we have to
redouble our efforts to investigate what is in store for our own
species in an environment of which DDT is now an established
component.

     DDT is only one of the many drugs that cause changes in the
metabolic capacity of the liver.  These changes are relatively
nonspecific, and the rapid destruction of steroid hormones appears to
be a coincidental byproduct of the liver cells' adaptation to DDT.
The individual exposed to DDT can therefore be expected to show a
changed reaction to a number of other chemicals and drugs, even under
conditions where the DDT alone shows little toxic effects.  The
long-term effects of such combinations are poorly understood.

     These effects are closely bound up with the deepest questions
of the functioning of DNA and RNA in the synthesis of proteins.
Appropriate research is making a fitful start today.  We can find no
more striking example of the unmistakable relevance of molecular
biology for global survival.

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