-23- 
30-watt, germicidal lamp giving a wave length of 2,537 angstrom units, 
whioh is a wave length normally filtered out of sunlight by the earth *s 
atmosphere* Recrystallized DDT (s*p. 108°C*), as well as several 
samples of plant-run material (s*p* 84-90 C*), was deposited on glasa 
plates from acetone solutions and aqueous dispersions prepared by 
different methods* After exposure to ultraviolet light for various 
periods, each plate was introduced into a cage containing house flies 
in suoh a way that all flies could and did contact the plate* Treated 
plates that were unexposed to the light affected the flies in 10-15 
minutes, but exposure to ultraviolet rays caused a loss in toxicity in 
proportion to the exposure* Residues of DDT deposited from solutions 
could be rendered nontoxic to flies by a 3-day exposure to this lamp* 
There seemed to be no difference in the three samples with regard to 
loss of toxicity, but there was some difference between the compositions 
used* The presence of the inert material in the dispersible composi- 
tions seemed to retard the rate of decomposition below that oocuring 
with residues from solutions, and, in general, the smaller the particle 
sise the more rapid was the rate of decomposition* This apparent de- 
composition of DDT as a result of exposure to light is of great interest 
and importance with regard to the residue problem* It is possible that 
weathered residues may have little or no toxioity to man and domestic 
animal s»~Goddin amd Swingle (179 )* 
EFFECT OF DDT ON YJILDLIFE 
The danger of DDT upsetting the balance. of nature is emphasized. 
— Teale (345) • 
An anonymous (31) writer called attention to Teale* s article aad 
deplored the idea of a world free of insects* DDT will prove a valuable 
boon in many ways but it can be an extremely dangerous boomerang un- 
less proper precautions are taken*— Conant (115 ) * 
An editorial quotes Teale and Pough on the dangers to beneficial 
insects and birds from the widespread and indiscriminate use of DDT— 
Anon* (66)* 
The 40-acre watershed of a small reservoir in Pittston, Pa», was 
treated at the rate of 5 pounds of DDT in 5 gallons of oil per aore* 
Three days later, after 0*75 inch of rain had fallen, an analysis of 
water samples from the reservoir indicated less than 1 part of DDT in 100 
