504 
AMERICAN JOURNAL OF BOTANY 
[Vol. 9, 
meters above the farthest visible rot, which had scarcely entered the lower 
side of our section IV. As the wood tested had been in the laboratory for 
about nine months, it had lost considerable of its water content before 
Fig. 3. Cross-sectional view of section VI, showing very clearly the appearance of the rot 
in the heartwood of the black locust. 
being tested, a condition, however, which should favor the inferences drawn 
from the results of the tests. 
Table 3. Tests of Blocks from Section VI 
Block 
Size (Inches) 
Crushing Strength 
Crushing Strength per Sq. In. 
1st Fail 
2d Fail 
3d Fail 
I 
2 
3 
IX 
1. 61 X 1.84 
1.6 XI.33 
23,000 
14,500 
23,500 
I5>500 
24,500 
16,500 
7,770 
6,813 
7,939 
7,277 
8,256 
7,746 
2X 
[The standard of 10,888 lbs. per sq. in. of perfectly sound locust is 
taken from Newlin and Wilson (191 7, p. 40).] 
It will be observed that the blocks from section VI had been materially 
weakened by from 2,000 to 3,000 pounds through the advance of mycelium. 
The blocks from section IV had been weakened in some cases by half. As 
is evident at once from a glance through the tables, blocks i, 2, and 3 all 
average about the same per square inch when compressed parallel to the 
