Germination and by Electrical Response. 
187 
Table VIII. 
Electrical response in volts . Strength and direction oj shock at head of columns. 
+ 1,000 
— 1,000 
+ 10,000 
— 10,000 
units. 
units. 
units. 
units. 
I. 
[-0-0025] 
+ 0-0087 
+ 0-0062 
— 0-0025 
+ 0-0019 
2. 
0 
0 
0 
0 
3- 
0 
0 
0 
0 
4- 
0 
0 
0 
0 
5- 
0 
0 
0 
0 
6. 
+ O-OOIO 
+ 0-0005 
— 0-0014 
— o-ooio 
7- 
0 
0 
0 
0 
8. 
0 
0 
— 0-0013 
0 
9- 
0 
0 
0 
0 
10. 
Average of 10 
+ 0-0054 
+ 0-0041 
+ 0-0091 
+ 0-0004 
+ 0-0008 
+ 0-0013 
+ 0-0018 
+ 0-0003 
experiments : — 
Table VIII. — Electrical responses of Hordeum vulgare treated with distilled water for 28 hours. 
Temperature = 23°C. Germination value = 50 %. 
(iii) Using different samples giving different germination values — 
50 per cent, and 85 percent, respectively. The results are most striking. 
Tables VII and VIII are examples of ten experiments on grains which 
were treated with distilled water on filter-paper for twenty-eight hours 
under the same conditions of temperature, moisture, &c., the electrical 
response of both samples being recorded the same afternoon to minimize 
any difference in the magnitude of the response due to slight differences of 
temperature, atmospheric conditions, &c., at the time of experiment. It is 
to be observed that the much lower average electrical response in the case 
of grains of the lower germination value is due to the larger number of 
embryos giving no response to electrical stimulus. Thus the 50 per cent, 
germination grain gives no response in about half the experiments. 
In Tables IX and X the record of the electrical responses in the 
case of the same samples of grain as above (85 per cent, and 50 per cent.) 
is tabulated. The galvanometric experiments were carried out when the 
grains had been soaked for twenty- five hours in distilled water at a tempera- 
ture of about 25 0 C. Here this point is brought out — that there is probably 
a time of maximum electrical response for these embryos just about the 
period when growth becomes obvious. This time would vary with the 
sample, and it is to be expected that the better the sample the sooner this 
response would be given. This is obviously a point of the greatest practical 
importance, and having ascertained that there is a parallelism between 
germinative capacity and electrical response, further experiments along 
these lines will evidently attempt to answer the question of the practical 
expert : ‘ What is the shortest time at which the electrical response will 
indicate the comparative vitality of a sample of seeds ? 5 
Table XI gives the average electrical responses of the four sets of 
experiments described above. 
