128 BOTANICAL GAZETTE ; [SEPTEMBER 
the curvatures mentioned. It is entirely possible for the upper 
portion of the root (the region of rapid elongation and above) to be 
dead and the tip to continue growth for a short time; in fact, many 
such cases were found. It is well understood that it is difficult to 
TABLE V 
CURRENT 0.2 MILLIAMPERE, 70 VOLTS; CRITICAL TIME 4 MINUTES 
Number | Direction | Time of Hips or} Number Dead ead 
Lot number of roots of exposure | gain (+) | showing | above above and 
used current poet 7 le = curvature only pa 
SP eae 5 220 —o.1 I 5 ° 
Se i eas Io i 225 —0.6 ° 4 6 
OF oe See ae ane Io } 230 —o.6 2 4 6 
Se eae 2I 240 —0.4 ° a 18 
Wei i 15 240 —0.7 ° ° 15 
ey erry Bons Bae 8 \ 270 —0.9 ° ° 8 
Booey cies 5 \ 270 —0.4 ° ° 5 
eo ee pe ae 5 4 300 —0o.6 ° ° 5 
_» 
TABLE VI 
CURRENT 0.15 MILLIAMPERE, 50 VOLTS; CRITICAL TIME 6 MINUTES, 
I5 SECONDS 
* Average Dead 
Number | Direction | Time of loss (—) or] Number | Dead ap 
Lot number of roots of hie! Sg gain ( rem nto above ee 
used CHEM Toads _— curvature only also 
Poe ey en 10 \ 300 —0.4 I 7 2 
PS a 15 Bee en ca 15 ly 360 —o.8 4 6 9 
Ay Oy TBS eee a 16 3 ae t 4 15 I 
to-G7. 5.60. 8 h 370 —0o.4 I 2 6 
Lee es 5 375 —o.2 ° ° 5 
14, 39; 28s ca 15 375 O09 I I T4 
» epee uae 10 375 OF ° ° io 
Sibel pee 5 4 390 —<O. 5 ° ° " 
16,75, 935. 34 15 390 —0.5 ° ° 15 
3,69 6 ae 15 Y 405 —0.5 ° ° 15 
OPIle Te) It { 405 —o.6 ° ° 11 
set up a criterion of measurement as to when death takes place; in 
fact, death has been called by some physiologists ‘(a reversible 
process.” The writer believes, however, that these criteria are 
sufficiently definite as used, and that they are scientifically sound. 
