
Tests with laboratory animals have shown that parathion is appreciably 
' more toxic than the other compounds mentioned here (Lehman, 1949). Corre- 
spondingly, feeding tests with this material involved concentrations of one- 
fourth that employed in the case of the other toxicants. At levels of 0.025 
and 0.0125 the kill was 89 percent and 50 percent respectively in 37 days. 
Numerous studies have demonstrated that the absorption and resultant 
toxic action of DDT to vertebrates is enhanced by administration in oil. 
In acute toxic studies on quail, Coburn and Triechler (196) found that oil 
solutions of DDT were )} to 5 times as toxic as equivalent amounts of the 
chemical administered in crystalline form. The primarily insectivorous diet 
of same birds would appear to provide a source of oil which might allow for 
increased absorption and assimilation of DDT obtained in the course of feed— 
ing. In an effort to approximate such a condition, a diet containing 0.05 
percent DDT was compared for effect with the same mixture including 0.5 per= 
cent of olive oil in addition to the insecticide. Groups of 20 birds held 
on each diet over a period of 37 days experienced essentially the same mor- 
tality and no difference in effect was noted. Amounts of food consumed and 
weight changes were comparable in the two groups. 
Speed of Action 
Further evidence of the relative toxicity to quail of these several 
insecticides may be seen in Table 2 which shows the speed with which lethal 
doses of the compounds were accumulated. The initial kill occurred first 
among DDT-fed birds, there having been two deaths on the 3rd day of feedin 
A complete kill of all 20 birds required nine days on the higher level of Fl nel 
medication with this material. Among chlordane-fed animals, initial mor- /O0/e 
talities occurred at both levels on the Lth day and the kill was complete 
at both levels by the 8th day. The 0.1 percent of toxaphene formulation ™ 
caused the first mortality on the 8th day and a complete kill by the 13th 
day. At the 0.05 percent concentration, neither DDT nor toxaphene produced ( 
complete mortalities within the 32-day test period. 

Studies with laboratory animals indicate that parathion is not stored 
in the body (Lehman, 1949). While the toxicant is not accumulative in 
tissues, there is no ‘doubt but that the effects of sub-acute dosing are 
accumulative as is revealed by the progressive die-off of the test animals. 
Weight Changes and Food Consumption 
Records of weight changes of birds and their food consumption (Tables 3 
and ) suggested that some of the insecticides under test may have had a re- 
pellent effect. In the case of chlordane- and toxaphene-fed birds, the 
weight losses at the 0.1 percent feeding level were nearly 50 percent. That 
this was due to a large extent to reduced feeding is indicated by comparisons 
of food consumption of test and check birds. Individuals on the chlordane 
diet on the average consumed_only about =seventh as much feed as did the 
checks . Toxaphene-fed birds at the 0.1 percent feeding Iével ate only about 
one~fifth as much as the control group. Weight losses were marked among 
birds on the parathion diet and to a lesser extent among the animals receiwing 
benzene hexachloride. The extent of these losses in weight (Table 3) were 
