Bui, 606, U. S. Dept. of Agriculture. 



Plate X. 



Penetration in Larqetooth Aspen— Heartwood (Populus grandidentata). 



1, piece No. 45 treated 30 minutes; 2, piece No. 46 treated 60 minutes; 3, piece No. 47 treated 120 

 minutes. Largetooth aspen showed very erratic penetration, which is well illustrated in the 

 three specimens shown. 



