100 MISSOURI BOTANICAL GARDEN BULLETIN 
as well as the chemical, which set particles of soil into a 
state of vibration resulting in greater growth. Kinney and 
Stone have shown that positive charges increased the growth 
of roots, while negative ones acted on the stems. This 
might be explained by the fact that the protoplasm of the 
roots and stems contains particles which are charged pos- 
itively and negatively. 
In general, it may be said that while some experiments 
seem to demonstrate the favorable effect of the electrical 
treatment, many others are negative or may be explained 
on other grounds. Before any definite practical application 
can be made of the use of electricity in growing plants, it is 
necessary to realize (1) the need for quantitative measure- 
ments of the electric discharge, (2) that a stimulus may 
act differently on the plant at different stages of its life, (3) 
that the effect of the stimulus depends upon its intensity, 
(4) that the effect of the stimulus depends on the time at 
which it is applied, and (5) that the effect of the stimulus 
may appear a considerable time after it is applied. 
\ 
EFFECT OF ELECTRICITY ON PLANTS 
(Averages for three years) 
Average | Average number| Date 
Treatment of plot Crop growth of of 
per plant fruits maturity 
MiecteiSed ss Tomato | 13 ft. 12 per plant | July 10 
Non-electrified ........ Tomato | 11 ft. 7perplant j|July 22 
Electrified ........... Corn 13 ft. 2per plant | Aug. 10 
Non-electrified ........ Corn 10 ft. 2per plant | Aug. 20 
Electrified ........... Beans 2.44 ft.| 14 Ibs. per plot | July 5 
Non-electrified ........ Beans 2.03 ft.| 10 lbs. per plot | July 12 
Electrified ........... Seva 900 fb. iii st vas July 10 
Non-electrified ........ PRY =) Pi TR Fiend s cies aclu July 20 
WINTER PROTECTION OF PLANTS 
Effective winter protection consists of assistance rendered 
by man to nature in its effort to carry plants through the 
hardships of severe winters. The attempts to afford pro- 
tection to tender plants generally result in a futile waste 
of time and money. It is difficult to protect a tender plant 
from frost when the thermometer stands below zero and the 
