Certain chemicals, again reminding us of radiation products like Strontium 90, have a peculiar
affinity for the bone marrow. Be nzene, a fre que nt cons tituent of insecticidal solvents, lodges in
the marrow a nd remains depos ited the re for pe riods known to be as long as 20 months.
Benzene itself has been recognized in medical literature for many years as a cause of leukemia.
The rapidly growing tis s ues of a child would also afford conditions most suitable for the
development of malignant cells. Sir Macfarlane Burnet has pointed out that not only is
leukemia increas ing throughout the world but it has become mos t common in the three- to
four-year age bracket, an age incidence s hown by no other dis eas e. According to this authority,
‘The peak betwee n three and four years of age can hardly have any othe r inte rpretation than
expos ure of the y oung organis m to a mutagenic s timulus around the ti me of birth.’
Another mutagen known to produce cancer is urethane. When pregnant mice are treated with
this chemical not only do they de velop cancer of the lung but their young do, als o. The only
expos ure of the infant mice to urethane was prenatal in thes e experiments , provi ng that the
chemical mus t have pas s ed through the placenta. In human populations expos ed to urethane
or related chemicals there is a possibility that tumors will develop in infants through prenatal
expos ure, as Dr. Hueper has warned. Urethane as a carbamate is chemically related to the
herbicides IPC and CIPC. Des pite the warnings of cancer experts , carbamates are now widely
us ed, not only as ins ecticides , weed killers , and fungicides , but als o in a variety of products
including plasticizers, medicines, clothing, and insulating materials....
The road to cancer may als o be an indirect one. A s ubs tance that is not a carcinogen in the
ordi nary s ens e may dis turb the normal functioning of s ome part of the body in s uch a way that
malignancy results. Important examples are the cancers , es pecially of the reproductive s ys tem,
that appea r to be linked with dis turbances of the balance of s ex hormones ; thes e dis turbances ,
in turn, may in some cases be the result of something that affects the ability of the liver to
preserve a proper level of thes e hormones. The chlorinate d hydrocarbons are precis ely the kind
of agent that can bring about this kind of indirect carcinogenesis, because all of them are toxic
in some degree to the liver. The sex hormones are, of course, normally present in the body and
perfo rm a necess ary growth-stimulating function in relation to the various organs of
reproduction. But the body has a built-in protection against excessive accumulations, for the
liver acts to keep a proper balance between male and female hormones (both are produced in
the bodies of both s exes , although in different amounts ) and to preve nt an exces s accumulation
of either. It cannot do s o, however, if it has been damaged by dis eas e or chemicals , or if the
s upply of the B-complex vitamins has been reduced. Unde r thes e conditions the es trogens build
up to abnormally high levels.
What are the effects? In animals , at leas t, there is abundant evide nce from expe rime nts. In one
such, an investigator at the Rockefeller Institute for Medical Research found that rabbits with
livers damaged by disease show a very high incidence of ute rine tumors , thought to have
developed because the liver was no longer able to inactivate the estrogens in the blood, s o that
they ‘s ubs equently ros e to a carcinogenic level.’ Extensive experiments on mice, rats, guinea
pigs , and monkeys s how that prolonged admi nis tration of es trogens (not neces s arily at high
levels ) has caus ed changes in the tiss ues of the reproduc tive organs , ‘varying from be nign
overgrowth to definite malignancy’. Tumors of the ki dneys have been induced in hams ters by
adminis tering es trogens. Although medical opinion is divided on the ques tion, much evide nce
exists to support the view that similar effects may occur in human tis s ues. Inves tigators at the
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