io8 
Balls . — Apparent Fallacies of 
Conclusions. 
This last failure made it abundantly clear that if the electrical test 
could not conveniently differentiate between such very sickly plants and 
their normal brethren, the primary object of the experiments — namely, 
a test for partial damage by root-asphyxiation — was doomed to failure, 
and the work has been for the time abandoned. 
The subject is evidently more important than it is commonly believed 
to be, and the writer hopes to re-examine it in the future with the desire 
of finding some clue to the apparent contradictions of the present data. 
The appliances will remain in use as a routine test for life and death. 
A possible hypothetical explanation of these negative results seems to 
lie in the form of the curve which may be plotted to represent the diminution 
of the response with loss of vitality. Thus the writer at first imagined that 
this curve would be fairly uniform, or even straight. If, however, it were 
logarithmic in form, the loss of vitality might progress steadily for some 
time without becoming noticeable by these comparatively rough experi- 
mental methods, while at a stage somewhat beyond that to which these 
tests have usually been carried, the slope would become rapid and notice- 
able, finally diving down to the death-point. 
On the other hand, the curve of fatigue (Table II) does not seem to 
admit of such an explanation, and fatigue from repeated shocks ends 
ultimately in death. Here the diminution in response is very marked 
between the first and second stimuli, then tolerably uniform until well 
beyond the reversing point — which might well be due to differential fatigue 
— and finally dying out until the response is merged in polarization errors. 
Lastly, the critical point at issue is the nature of ‘ vitality ’ itself, and it 
would seem to the writer that the present apparent contradictions offer 
a fair ground for physico-chemical inquiry. 
Summary. 
1. This note describes an unsuccessful attempt to utilize electrical 
response as a test for health in Egyptian cotton plants. 
2. During the tests it was discovered [a) that the initial magnitude and 
sign of the response obtained was dependent on the degree and direction of 
the asymmetry, anisotropy, or non-homogeneity of the two points of 
electrode contact ; (b) that fatigue by repetition of stimulation usually led 
to a gradual reversal of the direction of response before complete insensi- 
tivity was reached. 
3. The currents recorded as responses were the result of genuine 
differences provoked between the two portions of a tissue on which the 
electrodes rested. They were not pre-existent in the electrodes or tissues, 
and were not due to polarization. 
That they were, moreover, contingent on the 4 livingness ’ of the tissue 
is shown by the fact that boiling, fatigue, or tetanization abolished the 
response entirely. 
4. Two improvements in method were devised and used: 
