... we find ourselves facing a rising tide of biologically active, synthetic organic chemicals. Some tinker with our hormones. Some attach themselves to our chromosomes and trigger mutations. Some cripple the immune system. Some light up our genes and so enhance the production of certain enzymes. If we could metabolize these chemicals into completely benign breakdown products and excrete them, they would pose less of a hazard. Instead, a good many of them accumulate.

From the right to know and the duty to inquire flows the obligation to act.

Industrialized countries have disproportionately more cancers than countries with little or no industry (after adjusting for age and population size). One half of all the world's cancers occur in people living in industrialized countries, even though we are only one-fifth of the world's population. Closely tracking industrialization are breast cancer rates, which are highest in North America and northern Europe, intermediate in southern Europe and Latin America, and lowest in Asia and Africa.

In the world outside this glass room, songbirds are feeding and resting in the trees. Some will take off tonight and not land until they reach Venezuela. Sandpipers, plovers, and broad-winged hawks have already left for Patagonia and Panama. Bats are headed for caves in Kentucky and Tennessee. Out in the Atlantic, humpback whales pass by on their way to the Caribbean. Even now, Canada geese are honking toward us from Quebec. It is a good day for the beginnings of journeys.Every time I look at you, I think, Now I cannot die.

Here in the United States, a study of nearly 700 women in California showed an increased risk of fetal death among babies whose mothers lived near crops when certain pesticides were sprayed. The largest risks were found among pregnant women exposed during the critical first trimester and among those who lived in the same square mile where pesticides were used.

I have always been a big advocate of tap water-not because I think it harmless but because the idea of purchasing water extracted from some remote watershed and then hauled halfway round the world bothers me. Drinking bottled water relieves people of their concern about ecological threats to the river they live by or to the basins of groundwater they live over. It's the same kind of thinking that leads some to the complacent conclusion that if things on earth get bad enough, well, we'll just blast off to a space station somewhere else.

The study of how substances alter gene expression is part of the field of epigenetics. Some chemical exposures appear to turn on and turn off genes in ways that disregulate cell growth and predispose for cancer. From this perspective, our genes are less the command-and-control masters of our cells and more like the keys of piano, with the environment as the hands of the pianist.