14 TECHNIC-U^ BULLETIN 2 3 8, U. S. DEPT. OF AGRICULTURE 
all but one died, and the survivor died during the night. Body 
weights and other pertinent data are tabulated for convenient refer- 
ence in Table 3. The quantity of food eaten varied from 0.35 to 
Table 3. — Toxicity of commercial thallium-treated ffrain to rata 
WILD RATS 
Body weight of rats (grams) 
Grain offered 
Grain eaten 
Days 
until 
death 
Kernels 
Weight 
Weight 
Per cent 
Grams 
per kilo 
of body 
weight 
Number 
Orams 
Orams 
78 
16 
0.5 
0. 35 
70 
4.50 
3 
335. 
27 
1.0 
1.0 
100 
3.00 
3 
230 
24 
1.0 
1.0 
100 
4. 35 
4 
200 
66 
2.5 
0. 75 
30 
3. 75 
3 
325 
63 
2.5 
2.5 
100 
7.70 
3 
SO 
116 
5.0 
0.6 
12 
7.50 
3 
SO 
128 
5.0 
0.6 
12 
7.50 
3 
WHITE RATS 
195 
175 
157 
210 
182 
175 
210 
175 
160 
210 
175 
175 
12 
0.5 
0.5 
100 
2. 55 
4 
12 
0.5 
0.5 
100 
2. 85 
4 
13 
0.5 
0.5 
100 
3.20 
2 
26 
1.0 
1.0 
100 
4.75 
3 
25 
1.0 
1.0 
100 
5. .50 
3 
26 
1.0 
1.0 
100 
5. 70 
3 
62 
2.5 
2.5 
100 
11.90 
3 
64 
2.5 
2.5 
100 
14.30 
3 
58 
2.5 
2.5 
100 
15. 65 
3 
125 
5.0 
4.0 
80 
ly. 05 
3 
127 
5.0 
4. 15 
83 
23. 70 
3 
130 
5.0 
4.75 
95 
27. 15 
3 
2.5 grams, larger rats consuming the larger quantities. One gram 
of poisoned grain per rat killed two large rats. The minimum 
lethal dose was not determined, since all the test animals died, but 
evidently it is less than 3 grams of treated grain per kilogram of 
body weight (roughly equivalent to 30 treated kernels per pound 
of rat). Deaths occurred on the third and fourth days, even with 
very large doses of bait, which shows that thallium is a slowly acting 
poison to rats. 
Twelve white rats, weighing between 157 and 210 grams, were 
offered weighed and counted quantities of the grain at 12.15 p. m. 
on August 9, 1924. All uneaten food was removed at 9 a. m. on 
August 11, when all rats were found to be alive and in good condi- 
tion. One rat died the second day, the remainder on the third or 
fourth day, as shown in Table 3. A larger quantity of food was 
consumed by the white rats than by the wild rats, but over a longer 
period of time. During the same time interval, food consumption 
appeared to be about the same by the two varieties. No relation- 
ship was found between the quantity of poisoned grain eaten and 
the time until death; the earliest death occurred in a rat that had 
eaten 3.2 grams of grain per kilo, while others that had eaten five 
to eight times as much died a short time later. Thallium does not 
appear to kill rats rapidly, regardless of the doses consumed. Since 
