of the vis ible world around us. They reflect the web of life—o r death—that scientists know as
ecology.
But there is also an ecology of the world within our bodies. In this uns een world minute caus es
produce mighty effects ; the effect, moreover, is often seemingly unrelated to the cause,
appearing in a part of the body re mote from the area where the original injury was s us tained.
‘A change at one point, in one molecule even, may reve rbe rate throughout the e ntire s ys tem to
initiate changes in seemingly unrelated organs and tissues,’ says a recent summary of the
pres ent s tatus of medical res earch. When one is concerned with the mys te rious and wonderf ul
functioning of the huma n body, caus e and effect are seldom simple and easily demonstrated
relations hips. They may be widely s eparated both in s pace and time. To discover the agent of
dis eas e and death depends on a patient piecing together of many seemingly distinct and
unrelated facts developed through a vas t amount of res earch in widely s eparated fields.
We are accustomed to look for the gross and immediate effect and to ignore all else. Unless this
appears promptly and i n s uch obvi ous form that it cannot be ignored, we de ny the exis tence of
hazard. Even res earch men s uffer from the handicap of inadequate methods of detecting the
beginnings of injury. The lack of s ufficiently delicate methods to detect inj ury before s ymptoms
appear is one of the great uns olved problems in medicine.
‘But,’ s omeone will object, ‘I have us ed dieldrin s prays on the lawn many times but I have never
had convuls ions like the World Health Organization spraymen—s o it has n’t harmed me.’ It is
not that s imple. Des pite the abs ence of s udden and dra matic s ymptoms , one who handles s uch
materials is unquestionably storing up toxic materials in his body. Storage of the chlorinated
hydrocarbons, as we have seen, is cumulative, beginning with the smallest intake. The toxic
materials become lodged in all the fatty tiss ues of the body. When thes e res erves of fat are
drawn upon, the pois on may then s trike quickly. A New Zealand medical journal recently
provided an exa mple. A man unde r treatment for obes ity s udde nly developed s y mptoms of
pois oning. On examination his fat was found to c ontain s tored dieldrin, which had been
metabolis ed as he los t weight. The s ame thing could happen with los s of weight in illness.
The res ults of s torage, on the othe r hand, could be even les s obvious. Several years ago the
Journal of the American Medical Association warned strongly of the hazards of insecticide
s torage in adipos e tiss ue, pointing out that drugs or chemicals that are cumulative require
greater caution than thos e having no tendency to be s tored in the tis s ues. The adipos e tiss ue,
we are warned, is not me rely a place for the de pos ition of fat ( which makes up about 18 per
cent of the body weight), but has many important functions with which the s tore d pois ons may
interfere. Fu rthe rmo re, fats are very widely dis tribute d in the organs and tiss ues of the whole
body, even being cons tituents of cell membranes. It is important to re me mbe r, theref ore, that
the fat-s oluble ins ecticides become s tored in individual cells , where they are in pos ition to
interfere with the mos t vital and neces sary functions of oxidation and e nergy production. This
important as pect of the problem will be taken up in the next chapte r.
One of the mos t s ignificant facts about the chlorinate d hydrocarbon ins ecticides is their effect
on the liver. Of all organs in the body the liver is most extraordinary. In its versatility and in the
indis pens able nature of its functions it has no equal. It presides over so many vital activities that
even the s lightes t damage to it is fraught with serious cons equences. Not only does it provide
bile for the digestion of fats, but because of its location and the special circulatory pathways
that conve rge upon it, the liver receives blood directly from the diges tive tract and is deeply
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