As was seen in chapter 3, living organisms have evolved a means for receiving information about the environment in the form of nonvisual electromagnetic signals. To process it, organisms must also have developed an ability to discriminate among the infinite number of possible signals and to ignore those that were not useful. Although EMFs can be physiologically informational or can have characteristics that simulate intrinsic electrical signals found in growth-control and neural processes (see chapter 2), the bulk of the studies done to date used EMFs whose characteristics had no special physiological significance. The studies in part three show that the organism's prototypical response to such EMFs is the detection of the fields by the CNS and the subsequent adaptive activation of the organism's various physiological systems. Only when the organism's compensatory mechanisms are exhausted -when the EMFs are present too long, or at too high a strength, or when other factors are simultaneously present- do the effects become irreversible.
The cellular and molecular mechanism underlying the CNS's detection of applied EMFs are (for the most part) unstudied, and hence unknown. As we have shown in chapter 1 the study of bioelectrical phenomena has had a complex history involving many scientific, political, and economic factors. This combined with, ironically, the great intellectual triumphs of early twentieth century physics, produced a scientific Procrustean Bed1 regarding the biological effects of EMFs. The Bed consisted of an almost exclusive emphasis on the role of dipole orientation and heat-production as the molecular mechanisms for bioelectrical phenomena. Commonly, reports of biological effects were stretched to fit the Bed: the notion of "strong" and "weak" EMFs evolved in relation to how much heat was deposited in saline-filled beakers which were considered to represent the average electrical properties of living organisms. EMFs of 10,000-100,000 µW/cm2 were considered to be strong because they would noticeably heat the saline animal. Fields of 1000-10,000 µW/cm2, however, were held to be weak, because the saline animal's temperature change was so small that it was said, that if it were a real animal, the heat generated would probably be handled by the animal's homeostatic mechanisms. It was argued that fields below 1000 µW/cm2 were no more than electrical noise to the organism, and thus were entirely without physiological significance.
The thermal fiction took such firm root that it became impossible to establish that other mechanisms besides heat could be involved in the production of biological effects above 10,000 µW/cm2. This occurred despite the fact that no EMF-induced biological effects above 10,000 µW/cm2 have been replicated with heat applied via some other means. When reports of effects in the 1000-10,000 µW/cm2 range began to surface in the 1950's, the thermal hypothesis was extended to also apply in this range. The notion of differential heating was advanced, and its proponents argued that there were "hot spots" in the real animal, and that accounted for the observed biological effects. When reports of EMF-induced biological effects that extended beyond the Bed-below 1000 µW/cm2, 50 kv/m, 102 gauss-began to surface in the 1960's they were simply cut off: there developed unprecedented attacks against investigators who reported such effects.
The EMF Procrustean Bed has been destroyed by the weight of the number of excellent EMF studies: they exist, and it now becomes the business of science to investigate them and to learn their laws. Despite the interesting and provocative thoughts of some theoreticians and the tentative results of some experimentalists involving in vitro systems, there is still much to learn. Molecular processes that could explain EMF-induced biological effects are found in inanimate nature and, if they also occur in living systems, they would constitute one class of possible explanatory mechanisms. in addition, since the structural complexity of even the simplest living organism greatly exceeds that found in inanimate nature, it would be a mistake to expect that only molecular processes identified in purified materials could be candidates for the mechanism by which the organism detects an EMF. As we have frequently pointed out, solid-state biology may ultimately provide the answer - it may reveal mechanisms that simply do not exist in purified crystals.
Our best guess (and at the moment it is no more than that) is that the organism detects EMFs via cooperative dipole, or higher order, interactions in neural tissue-possibly peripheral nerves. An engagingly simple mechanical model of this notion has been described by Bowman (14). He assembled an array of dime-store magnetic compasses (Fig. 9.3), and described as follows the remarkably diverse range of states of the system that resulted when he passed a bar magnet nearby:
Fig. 9.3. Linear array of magnetic compasses (14).
The idea was first to set [the compasses] nearly touching in a row. The individual needles have a time constant, in pointing somewhere near to the magnetic north pole, of the order of a second. When they are close to one another, however, they interact to an extent that overshadows the field of the earth, and the time constant is of the order of, say, a tenth of a second. Thus they will point north to south, north to south, on down the line [Fig. 9.3a]. The experiment was set up so that north was normal to the axis of the array, and that gives a very stable sort of array. Bringing up a south pole gives a repulsion that will tend to displace the end needle. You can see, I am sure, that a quasi-static system will result, where we get something as shown in [Fig. 9.3b]. The angles of displacement will decrease, so that after the initial impulse a dynamic situation is established and the signal moves along, not too fast.
You can bring up the bar magnet slowly and dose, and maintain a static situation where equilibrium is propagated, so that the needles assume angles equally. The behavior is an exact analog of a gear train; that is, one turns this way, one that way, and so on [Fig. 9.3c]. It is very much like the bar where you turn one end and observe that the other end turns too. That is not too interesting.
However, if you look upon this as a dynamic rather than a quasi-static system, you can get some extraordinary phenomena that I cannot draw. With a little practice, bringing a south pole up just right, you can make the first compass spin all around and nothing is propagated down the line. The skill in my hand automatically introduces some random numbers, so the experiments were not reproducible. I can tell, nevertheless, of several things that can happen. If you bring the south pole up in a certain fashion, a nice signal goes along, with a complete flip-flop of every needle in the row, and a truly binary, bistable system exists.
On the other hand, if you do not do it in quite the same way, the signal will go down only so far, sometimes apparently even amplified through resonance, and somewhere along the line one of the needles will turn all the way around, and the signal will be reflected and go back again, never getting past a certain point. In other instances-you can run several hundred experiments an hour - you will have a section of several needles that just start spinning in a synchronous fashion until it finally dies out. Eventually it will settle down in one of the two stable states.
If you set up an (NxN) array of this sort, and then poke the thing with a bar magnet, I challenge any IBM machine to compute what will happen. The interactions are now exceedingly complicated.
We expect that something akin to this goes on at the molecular level when an organism detects an EMF. As Szent-Gyorgyi said (15): "Single molecules are not necessarily sharply isolated and closed units. There is more promiscuity among them [than] is generally believed."
1 Procrustes lived in ancient Greece, and it was his practice to make travelers conform in length to his bed. If they were too short he stretched them and if they were too long he chopped off their legs. Later, Procrustes wrote a learned paper entitled "On the Uniformity of Stature of Travelers."