FISH OIL AS ADHESIVE IN AESENATE-OF-LEAD SPRAYS 
19 
the oils were almost entirely dry (fig. 15). It was again examined 
August 13, but no burning by any of the oils was noted; on Septem- 
ber 2 the foliage still appeared waxy, with no burning apparent. As 
a further test, on September 6 a few cherry, hazel, and gray birch 
trees were sprayed with crude (raw) fish oil, the cheapest grade 
obtainable. The foliage was examined September 11, no signs of 
burning being found; still later examinations showed no injury. It 
may be inferred from these experiments that foliage would not be 
injured if the oil added to the spray mixture should be applied 
unevenly to the trees. 
SPRAYING NEAR BUILDINGS 
In the control of the gipsy moth or other insects it is sometimes 
necessary to spray shade or fruit trees in close proximity to dwelling 
houses or other buildings. When this is done, even with the utmost 
Fig. 15.— Appearance of leaves as affected by spraying: A, foliage sprayed with arsenate-of-lead 
mixture containing fish oil; B, foliage sprayed with raw fish oil; C, foliage not sprayed 
care, some of the material may drift upon buildings, and if allowed to 
dry would render them unsightly. Spray mixtures containing fish 
oil as an adhesive can be readily washed from buildings if the latter 
are drenched with water before the spraying is begun and again 
sprayed with a garden hose after the spraying with the insecticide is 
finished. The final water treatment should be applied while the 
spray material is still moist. This operation should be performed 
promptly, as the oil dries rapidly after the evaporation of the water 
in the spray material. 
CONCLUSION 
As a result of the experiments and tests conducted in the seasons of 
1921 to 1924, the materials which stand out preeminently as adhe- 
sives are linseed oil, fish oil, and corn oil, all three being drying oils, 
and for effectiveness they stand in the order named. Linseed oil 
