EED-SQUtLL POWDERS AS RATICIDES 
31 
many powders have rat units greater than 250, the value for fresh 
squill bulbs, also suggests that the toxic principle in squill bulbs may 
be hnked to some plant ingredient in a thermolabile condition, and 
that the toxic principle is liberated by heating to 80° to 100° C. 
STABIUTY OF SQUILL POWDERS 
Two red-squill powders stored in screw-top vials in the light for 15 
months showed no change in lethal dose. A 10 per cent squill bis- 
cuit that had been baked was as toxic a year later as the squill con- 
tent would require. A number of powders tested over a period of a 
year have shown no evidence of loss of activity. 
ACCEPTANCE TESTS 
To determine the palatabiHty of 10 per cent squill biscuit as com- 
pared with that of commercial samples of 5 per cent arsenious-oxide 
biscuit and 30 per cent barium-carbonate biscuit, several dishes were 
placed in a cage containing a starved white rat. Each dish contained 
more poisoned food than would be necessary to cause death by itself. 
After exposure from one to five hours, the dishes were removed, and 
the quantities of food consumed were determined. A number of 
tests were run simultaneously. With the weight of squill biscuit eaten 
considered as imity in each case, the ratio of control biscuit to 10 per 
cent squill biscuit was 2.6 :1.0; that of 5 per cent arsenious-oxide 
biscuit to 10 per cent squill was 0.17 : 1.0; and that of 30 per cent 
barium-carbonate biscuit to 10 per cent squill biscuit w^as 0.93 : 1.0. 
The absolute quantities of poisons consumed would then be in the 
ratio of 250 squill to 750 barium carbonate to 20 arsenious oxide. 
These figures are roughly proportional to the minimum lethal doses 
of the poisons imder consideration. Barium carbonate is approxi- 
mately one- third as toxic as squill powder; fed in three times the 
concentration, about equal quantities of bait are consumed. As the 
toxicity of arsenious oxide depends upon its degree of fineness, closer 
comparisons are not available. 
A field-acceptance test in comparison with phosphorus baits is re- 
ported by Teall.^ At Vienna, Austria, an organized 2-day rat-kill- 
ing campaign was held in January, 1927, phosphorus baits being used 
exclusively. Of 1,460,000 baits exposed, about 20 per cent were taken. 
In March, 1927, another 2-day campaign was undertaken, during 
which only squill baits were used. Of 1,260,000 baits exposed, more 
than 50 per cent were taken. It was noted that squill was taken in 
many houses where phosphorus bait had not been touched. 
The degree of acceptance of squill baits varies with the relative 
palatabiUty to rats of the foods with which the squill is mixed. Direc- 
tions for preparing and distributing red-squill baits have recently 
been published by the Department of Agriculture {24, P- S, 9). 
COMMERCIAL SQUILL RAT POISONS 
Three liquid squill extracts that had been offered for sale as rat 
poisons were tested. One was one-fourth and the other two were 
less^ than one-tenth as toxic as theil* labels would indicate. Two 
squill biscuits and three squill powders were found to correspond in 
toxicity to the labeled claims for squill content. 
«Teall, G. organization and results of the first VIENNA RAT-KiLUNG CAMPAIGN. (Second sup- 
plementary report to Report No. 6025 dated May 20, 1925, in reply to department's unnumbered instruc- 
tion of March 28, 1925, File No. 1027-1848.) [1927.] [Original, on file in Department of State, not seen. 
Copy on file in U. S. Dept. Agr., Bur. Biol. Survey.] 
