1908] POND—LATERAL ROOTS 421 
further advance is impossible, callus forms. Microscopical examina- 
tion of the flesh of a potato through which a radicle has passed 
showed no evidence of any digestive action. The collapsed cells 
with uncorroded walls could be easily found, though the full num- 
ber of cells required to occupy the volume of the tissue displaced by 
the radicle was not found in any given section. Compressed tissue 
too strongly compressed to allow a cell count was however present. 
No remnants of cells with frayed walls could be found. I did not 
See evidence of starch digestion in the immediate region through 
which the radicle passed. In many of the collapsed cells whose 
protoplasm appeared partially disintegrated, apparently intact starch 
Stains were easily visible. There was no evidence of an active 
autolysis of starch grains in the cells. 
Conclusion 
The lateral roots of Vicia Faba and of Lupinus albus push out 
from the central cylinder through the cortex mechanically and do 
hot have a digestive action upon the surrounding tissue. 
New Yor« Ciry 
