cancers among worke rs in the new lignite indus try in Saxony and in the Scottis h s hale indus try,
along with other cancers caus ed by occupational expos ure to tar and pitch. By the end of the
19th century a half-dozen s ources of indus trial carcinogens were known; the 20th century was
to create countless new cancer-causing chemicals and to bring the general population into
intimate contact with the m. In the les s than two centuries intervening s ince the work of P ott,
the environmental s ituation has been vas tly changed. No longer are expos ures to dangerous
chemicals occupational alone; they have entered the environment of everyone—even of
children as yet unborn. It is hardly surprising, therefore, that we are now aware of an alarming
increase in malignant disease.
The increas e its elf is no mere matte r of s ubjective impres s ions. The monthly re port of the
Office of Vital Statistics for July 1959 states that malignant growths , including thos e of the
lymphatic and blood-forming tis s ues , accounted f or 15 per cent of the deaths in 1958
compa red with only 4 per cent in 1900. Judging by the pres ent incidence of the dis eas e, the
Ame rican Cancer Society estimates that 45,000,000 Americans now living will eventually
develop cancer. This means that malignant disease will strike two out of three families. T he
s ituation with res pect to childre n is even more deeply dis turbing. A quarter century ago, cancer
in children was cons idered a medical rarity. Today, more American school children die of cancer
than from any other disease. So s erious has this situation become that Bos ton has es tablis hed
the firs t hos pital in the United States devoted exclus ively to the treatment of children with
cancer. Twelve per cent of all deaths in children between the ages of one and fourteen are
caused by cancer. Large numbers of malignant tumors are discovered clinically in children
unde r the age of five, but it is an even grimmer fact that s ignificant numbers of s uch growths
are pres ent at or before birth. Dr. W. C. Hueper of the National Cancer Institute, a foremost
authority on envi ronme ntal cancer, has s ugges ted that congenital cancers and cancers in
infants may be related to the action of cancer-producing agents to which the mothe r has been
expos ed during pregnancy and which pe netrate the placenta to act on the ra pidly developing
fetal tiss ues. Experiments s how that the younger the animal is when it is s ubjected to a cancer-
producing agent the more certain is the producti on of cancer. Dr. Francis Ray of the University
of Florida has warned that ‘we may be initiating cancer in the children of today by the addition
of chemicals [to food]...We will not know, pe rhaps for a generation or two, what the effects will
be.’...
The proble m that concerns us here is whether any of the chemicals we are us ing in our
attempts to control nature play a direct or indirect role as causes of cancer. In terms of
evidence gained from animal experiments we shall see that five or pos s ibly six of the pes ticides
mus t definitely be rate d as carcinogens. The lis t is greatly lengthened if we add thos e
cons idered by s ome phys icians to caus e leukemia in human patients. Here the evidence is
circumstantial, as it must be s ince we do not expe riment on human beings , but it is nonetheles s
impressive. Still other pesticides will be added as we include thos e whos e action on living
tis s ues or cells may be cons idered an indirect caus e of malignancy. One of the earliest
pesticides associated with cancer is arsenic, occurring in sodium arsenite as a weed killer, and in
calcium ars enate and various other compounds as ins ecticides. The as s ociation between ars enic
and cancer in man and animals is his toric. A fas cinating example of the cons equences of
expos ure to ars enic is related by Dr. H uepe r in his Occupational Tumors, a classic monograph
on the s ubject. The city of Reichens tein in Siles ia had been for almos t a thous and years the s ite
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