3i TECHNICAL BULLETIN 134, U. S. DEPT. OF AGRICULTURE 
Powders made by this process should kill white rats iii doses approx- 
imatiiii:: 250 to 500 milligrams per kilo of body weight, and should 
be stable for several years. 
Because of the variations in toxicity of different lots of squill, the 
minimum lethal dose of every lot of squill powder should be deter- 
mined by feeding it to rats in the laboratory before it is marketed. 
It should be fed in 10 per cent concentrations in ordinary rat food 
to white rats that have been deprived of all food for 18 hours. The 
minimum lethal dose is the smallest dose that kills all the rats within 
five days. At least five rats should be fed with each dose tested. This 
is necessary to insure essentially uniform toxicity in squill powders 
distributed commercially. As a result of feeding tests, great varia- 
tions in the potency of successive lots of powders may be reduced 
by properly mixing powders of higher degrees of toxicity with less- 
potent preparations, to produce the same standard potency. Such 
procedure would put a premium on the production of the most toxic 
squill powders, but would also permit the utihzation of less toxic 
preparations. 
As a standard of toxicity it is suggested that commercial squill 
powders having a minimum lethal dose of 1,000 milligrams per kilo 
of body weight be marketed, and that commercial squill baits having 
a minimum lethal dose of 10 grams per kilo be prepared. Such baits 
would contain 10 per cent of the standard squill powder (that is, a 
squill powder with a minimum lethal dose of 1,000 milligrams per 
kilo). If this standard bait is used, it would be necessary that a 
rat eat only 1 per cent of its body weight to obtain enough poison 
to Idll it. Many of the wild rats studied during this investigation 
weighed between 250 and 400 grams (8 to 14 ounces). From 2.5 to 
4 grams (one-twelfth to one-seventh of an ounce) of such a squill 
bait would be necessary to kill them. These experiments indicated 
that rats will readily eat much larger quantities of such baits. 
CONCLUSIONS 
Powdered red squill is toxic to rats; white squill is not. 
Powders prepared by directly drying unfermented, sHced red squill 
bulbs in an oven at 80° C. are usually more toxic than those pre- 
pared under other conditions. The lethal dose of squill powders 
prepared by this method is usually about 250 milligrams per kilo 
of body weight for white rats; wild (brown) rats are killed by some- 
what smaller doses. 
Cats, dogs, chickens, and pigeons were not seriously harmed by 
squill powder. Food poisoned with squill either was not eaten or, 
if eaten, was promptly vomited. Consequently it has been indicated 
that red squill is nontoxic to these animals under normal conditions 
and when exposed in the concentration recommended for rat poisons. 
Because of variations in toxicity, squill pow^ders should be tested 
before being marketed and adjusted so that 10 grams of 10 per cent 
squill bait will kill a minimum of 1 kilogram of rat. (One ounce 
will kiU 7 pounds of rats.) 
