ies in vogue. The reactions of different issues
were hitherto regarded as _special differences_. As against this, a
_continuity_ is shown to exist between them. Thus, nerve was universally
regarded as typically _non-motile_; its responses were believed to be
characteristically different from those of muscle. Dr. Bose, however,
has shown that nerve is indisputably motile and that the characteristic
variations in the response of nerve are, generally speaking, similar to
those of the muscle.

It was customary to regard plants as devoid of the power to conduct true
excitation. Dr. Bose had already shown that this view was incorrect. He
now showed, by experiment, that the response of the _isolated_ vegetal
nerve is indistinguishable from that of animal nerve, throughout a large
series of parallel variations of condition. So complete, indeed, is the
similarity between the responses of plant and animal, found, of which
this is one instance, that the discovery of a given responsive
characteristic in one case proves a sure guide to its observation in the
other, and the explanation of phenomenon, under the simpler conditions
of the plant, is found fully sufficient for its elucidation under the
more complex circumstances of the animal. Dr. Bose found 'differential
excitability' is widely present as a factor in determining the character
of special responses and showed that many anomalous conclusions, with
regard to the response of certain animal tissues, had arisen from the
failure to take account of the 'differential excitability' of
anisotropic organs. Hitherto Pfluger's Law of the polar effects of
currents was supposed to rest on secure foundations. But Dr. Bose showed
that Pfluger's Law was not of such universal application as was
supposed. He demonstrated that, above and below a certain range of
electromotive intensity, the polar effects of currents are precisely
opposite to those enunciated by Pfluger.

SENSATION

It was supposed that nervous impulse, which, must necessarily form the
basis of sensation, was beyond any conceivable power of visual scrutiny.
But Dr. Bose showed that this impulse is actually attended by change of
form, and is, therefore capable of direct observation. He also showed
that the disturbance, instead of being single, is of two different
kinds--_viz._, one of expansion (positive) and the other of contraction
(negative)--and that, when the stimulus is feeble, the positive is
transmitted, and, when t