138 BOTANICAL GAZETTE [SEPTEMBER 
B.—Root exposed to current of o.2 milliampere for four minutes; nega- 
tive electrode at tip. 
C.—Control, not exposed to current. 
PLATE II 
Cells from various portions of roots exposed to current, and from controls; 
magnifications for all figures approximately 580 diameters, with exception 
of fig. 8, about 500 diameters, and fig. 10, 550 diameters; all photomicrographs 
mounted so as to have positive electrode below. 
Fic. 1.—Normal cells (not exposed to Seats 8-10 mm. from tip in 
cortex. 
FIG. 2. els about 1 mm. from tip in central cylinder from root exposed 
to current of o.5 milliampere for sixty-five seconds; in the lower right hand 
ge dividing 
gaa ey Hoa. cortex of root exposed to current of 0.2 milliampere for 
one he this being one-fourth time required to kill root at this amperage. 
Fic. 4.—Normal cells from cortex about 3 mm. from tip. 
Fic. 5.—Cells of central cylinder about 8 mm. from tip; root exposed to 
current of 0.6 milliampere for twenty-five seconds. 
Fic. 6.—Cells from cortex about 10 mm. from tip; root exposed to very 
i ). 
G. 7.—No cells from cortex about 1 mm. from tip. 
Fic. 8.—Cells from cortex about 1 mm. from tip of root exposed to current 
of 0.6 milliampere for forty seconds. 
Fic. 9.—Cells from cortex about 4-5 mm. from tip; cytoplasm and nuclei 
also displaced; current of 0.3 milliampere for two and one-half minutes. 
1G. 10.—Same as fig. 9 but exposed to current only one and one-half 
minutes. 
‘Fic. 11.—From same region as fig. 8 
