Peru, the radioactivity of the coastal
plain is much the same as that of the
Mississippi region near New Orleans.
The local radiation at an elevation of
15,000 feet in southern Peru is only
slightly higher than that of the soils of
the coastal plain. Most of the houses of
Arequipa are built of a light rock called
“tuya” which is of volcanic origin. This
rock is 3 or 4 times as radioactive as the
soil near Lima.
There is considerable variability of
local radiation in some cases over small
distances. According to Millikan (6),
the gammarays on the Laurentian Shield
near Churchill, Manitoba, give 0.8 ion
cm-5 sec-? atm? of air, or 12 mr yr-},
while nearby the intensity on the glacial
sand is 35 mr yr-1. It may be of interest
that the radioactivity on the ice cap near
Thule, Greenland, in August 1956 was
less than 2 percent of cosmic rays.
A wooden building forms someshielding from local gammarays. In my own
house, the gamma rays on the first floor
give 60 mr yr-}, while in the back yard
the intensity is 95 mr yr-}. The rather
high value of 130 mr yr-! on the 23rd
floor of a major hotel in New York is
presumably owing to the material from
which the building is constructed.
The root mean square “noise” level of
the total radiation given in Fig. 1 is
about {60 mr yr-}. To find the effect on
the population, the local radiation must
>
a
contain something like 4 g of uranium
and 15 g of thorium per ton (5). In
I, S. Bowen, R. A. Millikan, H. V. Neher,
Phys, Rev. 46, 641 (1934).
H. Faul, Ed., Nuclear Geology (Wiley, New
York, 1954).
R. A. Millikan, unpublished results.
Summary Report of the Committee on the
Genetic Effects of Atomic Radiation, in Biological Effects of Atomic Radiation (National
Academy of Sciences, Washington, D.C., 1956).
15 March 1957
Human Poliomyelitis Antibodies
We have reported that if the lower
edge of a strip of filter paper is placed in
a suspension of a virus, the virus rises
on the paper and becames distributed in
a regular, reproducible manner (/}. The
experiments described in this report show
clearly that the upward spread of virus
is decreased when serum containing specific antibody ts placed in a band across
the filter paper (2). Serum without antibody does not exhibit this effect. The
“blocking” action of specific antibody
has been observed with polioviruses and
with six other viruses. The “blocking” of
polioviruses by human serums which
contain neutralizing antibody is type
specific.
Whatman filter paper No. 3 is cut into
strips 12 by 1.75 cm. Each strip is
marked off by light pencil lines into
l-cm spaces (numbered 1 to 12), suspended from a rubber stopper, and auto-
This has not been done. Perhaps it is
fortunate that most of the population of
the country lives where the radiations
due to cosmic rays and local radiations
are relatively low.
The dashed line near the bottom of Fig.
1 is taken from the Summary Reports
on the Biological Effects of Atomic Radiation of the National Academy of Sciences (7), Even though there is some
error in the determination of this value,
as well as considerable variation of fall-
out over the country, it is quite evident
that man-made contamination is. stil!
small compared with the changes in radiation from one part of the country to
another.
The data presented here are for
gamma rays only, since the walls of the
ionization chamber are too thick for
beta rays to penetrate, either from natu-
rally occurring or artificially produced
radioactive materials.
H. V. NEHER
Norman Bridge Laberatory of Physics,
California Institute of Technology,
Pasadena
References and Notes
1. R, A, Millikan, Phys. Rev. 37, 242 (1931).
2, A. R, Johnston, thesis, California Institute of
Technology (1956).
3. H. V. Neher, Rev. Sei. Instr. 24, 99 (1953).
31 MAY 1957
|
io
ar
| me
wn
—
percent NaCl containing
=
diluted virus is placed in a sterile bottle
surroundedby ice. The serum to betested
(previously inactivated at 56°C) is then
Vdistributed evenly over spaces 3 and 4
of the filter paper. The paper is placed
in the bottle containing the virus with
only the lower half of space 1 below the
surface of the virus suspension (see diagram of apparatus, Fig. 1). After 1 hour
the strips of paper are removed, and each
paper space is cut off and placed in a
monkey kidney tissue-culture tube. Tis-
sue culture tubes are incubated and observed for virus cytopathogenic effects
in the usual manner. Neutralizing anti-
body titers of the serums used in the
paper tests are determined by standard
tissue culture methods.
Fifty-two successive tests (104 paper
strips) with 14 human serums have given
virtually identical results. Virus was detected by tissue culture on every wet
space of every paper strip on which
serum containing no antibody had been
placed. In contrast, no virus was found
above space 6 on any of the paperstrips
that were treated with serum which contained type-specific poliovirus antibody.
No virus was detected above space + in
the vast majority of such strips. Figure
1 shows examples of typical results. In
a
—
g VIRUS FOUND ON
PAPER SPACE
oe
a
< 4)
Da
—
Be
2
|
SERUM
ANTIBODY TITRE
SPACES WET BY RISE
OF FLUID.
o |
a |
HT.OF COLUNN@PAPER
ie
a 7
ul
a
10 percent
bouillon broth. Thirty milliliters of the
f
New Method for Detection of
be weighted according to the population.
claved. Poliovirus cultivated in monkey
kidney tissue is diluted to a concentration of 100 TCD... per milliliter in 0.85-
NO VIRUS FOUND
ON PAPER SPACE
=
oe
md
am
i
“4
1 Ee el
A BBB
aR TS
A BAB
BY STANDARD 0 [:64] 0 16466464] 0 1:8] 0 64 0 1:64] 0 1:64
METHODS
SERUM ON PAPER
QUANTITY: 1 tf dE] tt ].05 05 025.0257 1
DILUTION: UNDIL. UNDIL. 1:2 1:4 UNDIL.
UNDIL.
UNDIL.
VIRUS CONCENT.
INRESERVOIRS.| 100
100
100
100
{,000
(1005 /mi.)
EXPER|
|
2
3
4
5
*® SERUM PLACED ON THESE SPACES
{f
]
a
CI
i
CI
ca
Dr
EVIRISe
NUN
DIAGRAM 0
APPARATUS
Fig. 1. Sample experiments showing that serum which contains type-specific antibody
decreases the extent of the spread of type 2 poliomyelitis virus on filter paper.
4089