880 
GENETIC AND BIOLOGICAL EFFECTS OF RADIATION 
10 15 20 25 30 35 40 45 
IRRADIATION DAYS (lOOr/day) 
Figure 3. — Mortality in 2 breeding lines within 3 breeds of swine (Duroc, D-1 and D-2; Hampshire, H-1 and 
H-2; and Yorkshire, Y-1 and Y-2) exposed to whole-body ""Co gamma radiation in daily doses of 100 R 
until death. 
mals affected with genital, intestinal, and hep- 
atic tumors was relatively higher in the ir- 
radiated swine than in the controls (Table VI). 
These tumors occurred earlier in the irradiated 
Table VI. — The Number of Irradiated and Control 
Swine Affected with Genital, Intestinal, and Hepatic 
Tumors 
No. of 
Animals 
No. Subjected 
to Postmortem 
Examination 
Genital 
Tumors 
Intestinal 
Hepatic 
Controls 
Males 
23 
23 
1* 
0 
1 
Females 
12 
11 
7** 
0 
0 
Irradiated 
Males 
.. 41 
41 
0 
8 
13 
Females 
30 
28 
23 
6 
5 
♦Urethral neoplasm. 
**Six animals had tumors of the uteri and/or broad ligaments; 
one animal had an ovarian tumor. 
swine (Figure 7), this fact suggesting temporal 
advancement due to irradiation. No tumors 
were found in the controls less than 9 years of 
age except one animal affected with an ovarian 
tumor. The relatively immense size and weight 
(up to 27 kg) of the genital tumors in the ir- 
radiated swine contributed directly to deaths. 
These tumors were quite small in the controls 
and were not of significance relative to causes 
of deaths. The intestinal adenocarcinomas were 
in most instances important factors in the 
deaths of the swine so affected. The hepatomas 
presumably were not significant etiologic agents 
in the deaths of any of these swine. The specific 
cause of death was frequently difficult to iden- 
tify. This was especially true in the aged swine 
