34 
BULLETIN 1422, U. S. DEPARTMENT OF AGRICULTURE 
Actual yield data from trees tapped with this knife are lacking, 
but the common report is that increased yields result from its use, 
that injury to the trees is reduced, and that the time consumed in 
Fig. 10. — A Hevea tree at Seringal Miry, Manaos, which is being tapped with the Amazonas knife. 
On the right side of the tree the knife was used for incision also, and the excrescences may be easily 
seen 
tapping is not increased. The knife is constantly coming into wider 
use, and on some seringals it has completely supplanted the macha- 
dinho. 
