D. G. BROWN 
885 
lOr 
0 
Males 
Y = 8.77 + (-O.OOIOX) 
Females 
Y=8.I3 + (-0.0034X) 
100 200 300 400 500 600 700 
Dose (Rads) 
Figure 8. — Regression of postirradiation survival time on dose, with 68% confidence bands about the regression 
lines, for male and female swine exposed to mixed gamma-neutron (bomb) and X-radiation. (Life shortening 
for the total population was approximately 3% per 100 rads.) 
eral? I realize they usually don't live this long, 
but I've been unable to find any. 
Dr. Brown : To my knov^^ledge there are two 
aged swine herds in the U. S. vi^hich have been 
used to study the normal aging process. One is 
at Iowa State University. This herd should now 
be about 10 years old. At nine years of age no 
tumors had been found in these swine. The other 
herd is in 'New Jersey and was used by the 
Veterinary School of the University of Pennsyl- 
vania for studies with atherosclerosis. Some of 
the animals which they used, and had an op- 
portunity to perform autopsies on, apparently 
lived to be about fifteen years old. The incidence 
of tumors in these swine was approximately 3 
per cent for the hepatoma and 3 per cent for the 
intestinal tumors, however, the intestinal tumors 
which they found in these swine v^ere in the 
colon rather than in the small intestine. 
McClellan G. Blair, ARCO Nuclear Co.: 
(Inaudible) 
