purpos e in birds and bacteria, in me n and mice. The fact of insecticide storage in the germ cells
of any s pecies s hould theref ore dis turb us , s ugges ting comparable effects in human beings.
And there are indications that thes e chemicals lodge in tiss ues concerned with the manufacture
of germ cells as well as in the cells themselves. Accumulations of insecticides have been
dis covered in the s ex organs of a variety of birds and mammals—in pheas ants , mice, and guinea
pigs under controlled conditions , in robins in an area s prayed for elm dis eas e, and in deer
roami ng wes tern fores ts s prayed for s pruce budworm. In one of the robins the concentration of
DDT in the tes tes was heavier than in any other part of the body. P heas ants als o accumulated
extraordinary amounts in the tes tes , up to 1500 parts per million. Probably as an effect of such
s torage in the s ex organs , atrophy of the tes tes has been obs erved in experi mental mammals.
Young rats expos ed to methoxychl or had extraordina rily s mall tes tes. When young roos ters
were fed DDT, the tes tes made only 18 per cent of their normal growth; combs and wattles ,
dependent for thei r development upon the tes ticular hormone, were only a third the normal
size. The s permatozoa thems elves may well be affected by los s of ATP. Experiments s how that
the motility of bull sperm is decreas ed by dinitrophe nol, which interferes with the energy-
coupling mechanis m wi th inevitable los s of energy. The s ame effect woul d probably be found
with other chemicals were the matter investigated. Some indication of the possible effect on
human beings is seen in medical reports of oligos permia, or re duced produc tion of
spermatozoa, among aviation crop dus te rs applying DDT....
For mankind as a whole, a possession infinitely more valuable than individual life is our genetic
heritage, our link with pas t and future. Shaped through long eons of evolution, our genes not
only make us what we are, but hold in their minute beings the future—be it one of promis e or
threat. Ye t genetic dete riorati on through man-made agents is the menace of our time, ‘the las t
and greatest danger to our civilization’. Again the parallel between chemicals and radiation is
exact and inescapable. The living cell assaulted by radiation suffers a variety of injuries: its
ability to divide normally may be destroyed, it may s uffer c hanges in chromos ome s tructure, or
the genes , carriers of hereditary mate rial, may unde rgo thos e s udden changes known as
mutations , which caus e them to produce new characteris tics in s ucceeding generations. If
especially susceptible the cell may be killed outright, or finally, after the passage of ti me
measured in years, it may become malignant.
All thes e cons equences of radiation have been duplicated in laboratory s tudies by a large group
of chemicals known as radiomimetic or radiation-imitating. Many chemicals used as
pes ticides—herbicides as well as insecticides—belong to this group of s ubs tances that have the
ability to damage the chromosomes, interfere with normal cell division, or cause mutati ons.
These injuries to the genetic material are of a kind that may lead to disease in the individual
expos ed or they may make thei r effects felt in future generations. Only a few decades ago, no
one kne w thes e effects of either radiation or che micals. In thos e days the atom had not been
split and few of the chemicals that were to duplicate radiation had as yet been conceived in the
tes t tubes of chemis ts. Then in 1927, a profes s or of zoology in a Texas univers ity, Dr. H. J.
Muller, found that by expos ing an organis m to X-radiation, he could produce mutations in
s ucceeding generations. With Muller’s dis covery a vast new field of scientific and medical
knowledge was opened up. Muller later received the Nobel P rize in Medicine for his
achievement, and in a world that soon gained unhappy familiarity with the gray rains of fallout,
even the nons cientis t now knows the potential results of radiation.
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