Evening star., 1952-12-08
Evidence Casts Doubt
On Cancer Heredity
Experts Find Environment
More Potent Than Genes
By Thomas R. Henry

more TOtent non 9eHeS
By Thomas R. Henry
There is absolutely no evidence that
cancer is hereditary in human beings.
This is the opinion of the Committee
on Growth of the National Research
Council, composed of some of the coun-
try'S foremost cancer experts.
Numerous experiments with animals
have shown very high hereditary sus-
ceptibility to cancer - in some cases as
high as 100 per cent. But this Is true
only of pure-bred strains bred for many
generations with the single idea of pre-
serving this single hereditary factor for
experimental purposes.
Man, the annual report of the COM
mittee points out. Is not a pure-bred
animal and cannot be. Every possible
hereditary tendency in the race is mixed
up.
''The mating habits of man are SO
haphazard." says the report, that the
existence of human strains with diff
ferent sensitivities to cancer is incon-
ceivable."
Despite this, the report stresses,
genetics remains one of the most i'm
portant tools in cleaning up the ever
more complex cancer mystery 1t now
is generally accepted that the cancer
cell, with its faculty of multiplying at
a rapid rate, is mutant from the
normal body cell which does not carry
on the same chemical reactions.
Theory Giving Way.
TT,ztH \
that all mutants-single cells, plants or
animals with a changed hereditary pat
tern-were due to- changes brought
about in the invisibly minute genes, the
ultimate carriers of heredity. They are
arranged in strings, known as chromo-
Somes, which float in complex semi
liquid, cytoplasm. The cytoplasm, it was
presumed, played an actual role in
heredity.
Now attention has been focused on
inviSibly minute particles contained in
the cytoplaSm itself which apparently
also are carriers Of heredity. They do
not function independently but in CO.
operation with the genes.
When cell divides, exactly the same
number of genes 60 into each half. This.
recent experiments have indicated, is
not true of the so-called plasmagenes
in the cytoplasm whose rate of null
tiplication seems subject to considerable
variation. Part of their significance in
the cancer problem is the demonstra-
ton that they are more subject to the
influence of environment than the genes.
Rise in Sea Level
For the past 20 years the Atlantic
Ocean has been crawling up over the
East Coast of the United States seven
times as fast as during the Is proceed
ing years.
Tidal guage records along the Eastern
Seaboard show a rise in sea level Of
about two-tenths of an inch a year.
Ever since 1895, when recordings started,
there has been slow rise which now
seems to have been greatly accelerated.
This has just been reported to the
Office of Naval Research by Dr. George
F.. Carter of Johns Hopkins University,
who is carrying out study of CheSa-
peake Bay beaches under Navy grant.
If this rate continues, he points out,
the result will be catastrophe for areas
like the great vegetable growing coun-
tryside of Eastern Shore Maryland and
parts of Delaware and Virginia. If the
same rate of increase had been con-
tinuous since Colonial times, he says.
sea level all along the coast would be
six feet higher than at present and the
sites of now hourishing cities would be
washed by the tides.
1t, is obvious from study Of docks built
before the Revolution that this has not
happened. They are not six feet too
low today.
Extensive Thawing Cited.
Part of the explanation, he says, is
that during the present century there
has been extensive thawing in high
latitudes. Glaciers have been melting,
the area of permanent freezing of the
soil below the surface has been dimin-
ishing, and forests have advanced north
ward. All this has put more water in
the sea. Then land has been rising in
some places, due to removal of the
weight of the ice. This has caused
the ocean to overflow elsewhere.
Actually, during the past century, DR..
Carter says, Chesapeake Bay itself has
not become much deeper due to the
wash-off from the land which has built
up the bottom even faster than the sea
has risen.
The studies show, he points out, that
at times in the remote past the sea
level has been as much as rs feet beyond
that at present. There also was a time.
quite recently in the geological time
scale, when 1t was 800 feet lower than
at present. At that time the bay must
have been a great valley with many
CT 1