126 BOTANICAL GAZETTE [SEPTEMBER 
The criteria by which a root was judged to be dead, living, or 
partly dead are the following. When a root after twenty-four 
hours was distinctly shriveled and drying in the upper region, that 
TABLE I 
CURRENT 0.6 MILLIAMPERE, 120 VOLTS; CRITICAL TIME 52 SECONDS 
_ Sone Time of Average ead 
ESS Numbes Direction sapouare pepe ( ty oe betas above ae 
used current seconde a curvature only also 
5 aN ee ee ee 5 15 +0.5 4 5 ° 
Wee ee een 5 30 +O.2 am 5 fo) 
Soa eset 5 40 —0.4 4 4 I 
Ee gl ere 5 45 —0.5 3 5 ° 
Cie ein seas 5 50 54 3 3 2 
Oe ess pees ee 6 50 art Sek 2 zz 4 
TEES Io Pe. —I.I ° fe) Io 
TS PTS ces: to 52 —1.2 I I 9 
og ct) Cee eters Io 55 —1I.3 ° ° To 
POPES oe II s 55 —I.1 I I To 
POR Wor ae Mew 5 s 60 —0.9 ° ° 5 
1 ens Ee 5 s 60 —o.16 ° ° 5 
TABLE II 
CURRENT 0.5 MILLIAMPERE, IIO0 VOLTS; CRITICAL TIME 65 SECONDS 
Pee Time of | Averag' Dead 
Lot number pies a“. set gad gloss a, eae Eine wg fogs 
used current ieee a ot curvature only alss 
Ne sie es 5 20 +1.0 3 5 ° 
PEN og rte 5 4 40 +0.1 3 4 I 
Yee re ee 5 ‘ 45 << Og 4 4 I 
Seve cans 5 \ 50 0.90 4 4 I 
Oe eee chess 5 55 —I1.1 2 2 3 
baer al oa 5 s 55 —O.1 a! 4 T 
Vek i ae 10 { 60 —0.3 I 2 8 
Z, Os iliiceig. .. I5 60 —0.6 5 4 Il 
48, 27, 10.0 50%6.5 16 y 60 —0O.7 3 6 to 
MEO. aa 12 \ 65 —0.7 I ¥ it 
T4F IB ee 10 h 65 —1I.I ° ° 10 
a CR a i I 7O —o.8 ° ° 5 
ro Papa agipaeeesin ee 5 70 —1.0 ° ° 5 
portion was regarded as dead. In nota single case in all tests made 
did this part revive after having reached this stage. A chalky 
white appearance of the first 4 or 5 mm. of tip, together with the 
