296 
Journal of Agricultural Research 
Vol. VIII, No. 8 
injury in every case. The least was a streak running up 11 inches 
and down 3 inches. In the worst injury the entire branch above the 
bandage was killed, and a dead streak ran down 10 inches. Between 
these two extremes there were all gradations. In comparison with the 
injury through unpainted wounds, it was clear that the paint had in 
some cases given a partial protection, but in others little or none. 
A few wounds were left unpainted in the center to see whether the 
arsenical entering through the wood at that point would work outward 
and cause an injury to the bark. The failure of the paint to protect 
when applied to the entire cut surface leaves the result doubtful in these 
cases. 
Twenty-one other wounds of a similar nature were painted with white- 
lead paint as soon as made, and, after an interval for drying, 10 gm. of 
copper aceto arsenite was applied to each. On four of these the paint 
was allowed to dry for 6 hours before treatment, on six others it was 
allowed to dry for 7 hours, and on the remaining eleven 24 hours. The 
work was done in dry, sunny weather; and even in 6 hours the paint 
showed considerable evidence of drying. In 24 hours it seemed quite 
dry, though not very hard. In general, the paint under these conditions 
reduced the amount of injury very materially as compared with un¬ 
painted wounds similarly treated, and yet in nearly every case streaks 
several inches long were produced and in four cases the entire branch 
above the bandage was killed. In three of these four cases the paint 
had dried for 7 hours and in the other 24 hours. 
Eleven branches varying in size from to 3^ inches were cut off 
several inches from the large limbs on which they grew, so that long stubs 
were left. These stubs were painted on the cut ends and for about 2 
inches back on the uninjured bark. Some were given one coat and some 
two, with an interval of 24 hours for drying after each coat. The end of 
each stub was treated with 25 gm. of Baker’s calcium arsenite, the band¬ 
age being applied in the form of a cap and covered with a dental rubber 
dam. In some cases, especially where two coats of paint had been 
applied, the action of the chemical was considerably lessened, but in the 
majority, including some with two coats of paint, the injury was excessive, 
running down the stub and into other parts of the tree. In no case was 
the protection complete. 
Nine other stubs were similarly treated with spar varnish, but this 
offered no better protection than the paint. 
It should be noted in this connection that in these large stubs the press¬ 
ure of sap was so great as to form blisters under the paint and varnish; 
and these often broke open, which would easily account for the injury. 
This condition, however, did not occur on the wounds on smaller limbs. 
If it were a matter of great practical or scientific importance, it is pos¬ 
sible that a covering could be found that would give better protection 
than either white-lead paint or varnish. 
