It is known to-day that what nature reveals so strikingly in the case of the electric fish, is nothing but the manifestation of a principle at work in the bodies of all beings endowed with sensation and volition - in corporeal terms, with the duality of a nervous and a muscular system - and therefore at work also in the human body. Observation has shown that the activities of these two systems in man and animal are accompanied by the occurrence of different electric potentials in different parts of the body. Plate A, Fig. iii, shows the distribution of the two polar electric forces in the human body. The bent lines in the diagram stand for curves of equal electric potential. The straight line between them is the neutral zone. As might be expected, this line runs through the heart. What seems less obvious is its slanting position. Here the asymmetry, characteristic of the human body, comes to expression. If we remember that the nervous system represents the salt-pole, and the metabolic system the sulphur-pole, of the human organism, and if we take into account the relationship between levity and gravity at the two poles, we can see from the distribution of the two electricities that the coupling of levity and gravity at the negative pole of the electrical polarity is such that levity descends into gravity, while at the positive pole gravity rises into levity. Negative electricity therefore must have somehow a 'spherical' character, and positive electricity a 'radial'. This finding is fully confirmed by electrical phenomena in the realm of nature most remote from man (though it was an effort to solve the enigma of man which led to the discovery of this realm). Since Crookes's observations of the behaviour of electricity in a vacuum it is common knowledge that only the negative kind of electricity occurs as a freely radiating force (though it retains some properties of inertia), whereas positive electricity seems to be much more closely bound to minute particles of ponderable matter. Here again we find gravity-laden levity on the negative side, levity-raised gravity on the positive. The same language is spoken by the forms in which the luminous phenomena appear at the two poles of a Crookes tube. Fig. i on Plate A represents the whole phenomenon as far as such a diagram allows. Here we see on the positive side radial forms appear, on the negative side planar-spherical forms. As symbols of nature's script, these forms tell us that cosmic periphery and earthly centre stand in a polar relation to each other at the two ends of the tube. (Our optical studies will later show that the colours which appear at the anode and cathode are also in complete accord with this.)