244 TWENTY-FIFTH ANNIVERSARY REPORT. 
into solution if applied while the dew is present; and if distributed 
when the plants are dry, the powder adheres only to the upper sur- 
face of the leaves. On the basis of these results, one pound of 
paris green to one hundred and sixty gallons of water, with enough 
lime to neutralize any soluble arsenic present, was recommended as 
the spray best adapted for the treatment of the cabbage leaf-eating 
insects. Attention was also called to the new arsenical, gypsine, now 
known as arsenate of lead, which by reason of its safe and adhering 
qualities appeared to be a promising poison for spraying cabbages. 
Subsequent experiments have shown that arsenate of lead is the 
most efficient poison for the treatment of plants with smooth foliage, 
such as cabbage, because of its superior adhesiveness. 
With the appearance of the cabbage looper (Autographa brassi- 
cae) and its growing importance as a cabbage pest, efforts were then 
directed to compounding a soap® to make arsenicals more adhesive 
to cabbage foliage. The necessity for this addition to the usual 
spray was that the caterpillars of this species work largely on the 
undersides of the leaves, where they may remain unnoticed until 
much damage has been done, and where only very thorough appli- 
cations of remedies will affect them. They are also active in 
movements and discriminating in taste so that they quickly abandon 
feeding places which show traces of poison or other foreign -sub- 
stance. To obtain successful results it was found that the applica- 
tions of the poison must be made thoroughly so that every portion of 
the surface of the leaves is protected. 
After repeated tests, an excellent material for securing uniform 
distribution and perfect adhesion was found in a resin-lime mixture. 
In preparing this mixture it is necessary to make, by slow boiling, 
a stock solution of five pounds resin, one pound concentrated lye 
and one pint of fish oil. For use, one gallon of this stock material 
was mixed with three gallons milk of lime, one-fourth pound paris 
ereen and sixteen gallons of water. 
The resin-lime mixture received its first test upon cabbages in 
1896. The results were an entire success and protection was 
afforded to the plants to the end of the season, notwithstanding 
heavy rains. In this experiment, comparative tests were made of 
the paris green and resin mixture in comparison with bordeaux 
mixture and paris green, and paris green mixed with flour. It was 
estimated by the owner that the plats treated with the poisoned 
® Buls. 83 and 144; same in Rpts. 13:737-766 (1894) and 17:380-413 (1808). 
