18 TECHNICAL BULLETIN 2 3 8, U. S. DEPT. OF AGRICULTURE 
Table 5. — The toxicity of commercial thallium compounds to white rats 
C 1 
No 
Acceptance 
Rats 
fed 
Number of rats dyine after period stated 
when fed 20 milligrams per kilo 
r> 
Rats 
leu 
Number of rats djing 
after period stated 
when fed 40 milli- 
grams per kilo 
1 
day 
2 
days 
3 
days 
4 
days 
5 
days 
6 
days 
7 
days 
1 
day 
2 
days 
3 
days 
4 
days 
1 
Poor 
Nu m- 
ber 
3 
1 
1 
1 
Nvm- 
ber 
3 
2 
1 
2 
do 
3 
1 
1 
1 
3 
3 
3 
Unknown.. 
3 
1 
2 
3 
2 
1 
4 
Low 
3 
1 
1 
1 
3 
2 
1 
5 
Ready 
3 
2 
1 
3 
3 
6 
Unknown.. 
3 
1 
2 
3 
1 
2 
Of the 18 rats fed 20 milligrams per kilo, 14 consumed all their 
food within 15 to 20 minutes, 2 in about an hour, and the other 
2 during the night. Of the 18 fed 40 milligrams per kilo, 12 fin- 
ished eating within 15 to 20 minutes, 3 within an hour, and 3 during 
the night. No differences were noted in the acceptance of sample 
1, which had a poor field acceptance, and of sample 5, which was 
readily taken in the field. Time until death was somewhat longer 
in this series than in the preceding tests, but too few animals were 
used to regard this as significant. Sample No. 6, an American 
product, appeared to kill as rapidly if not more so than the German 
sample. No. 3. 
These feeding experiments failed to reveal any differences in 
acceptabilit}^ or toxicity in the six samples studied. Further inten- 
sive feeding experiments would be needed upon several hundred rats 
to determine whether significant differences in time between feeding 
and death might be expected. It may be that rats are less suscep- 
tible to foreign odors or tastes than are prairie dogs, when poisoned 
baits are offered them; or the nature of the bait with which the 
poisons are mixed may be a contributing factor in the acceptance 
or rejection of specific lots of poisoned baits. 
PHYSIOLOGICAL ACTION ON RATS 
Rats appeared restless and uneasy 24 hours after the consumption 
of a fatal dose of thallium. Loss in appetite usually occurred, fol- 
lowed by respiratory distress, labored breathing, and death by res- 
piratory failure. Post-mortem, the heart was engorged; the lungs 
and liver usually congested, and in some cases the kidneys and spleen ; 
the stomach lining was hemorrhagic. Alopecia was not observed in 
the comparatively short time before death; surviving rats showed 
some losses of hair 10 to 15 days after feeding. 
TOXICITY OF THALLIUM TO RABBITS BY INTRAVENOUS INJECTION 
The quantity of thallium as chemically pure thallium sulphate 
that would kill rabbits was also determined. Aqueous solutions con- 
taining 0.5 to 1.0 per cent of thallium (5 to 10 milligrams of thallium 
per cubic centimeter, or 6.18 to 12.35 milligrams of thallium sulphate 
per cubic centimeter) were freshly prepared and injected into the 
