September 14, 191 1] 



NATURE 



365 



will not dwell upon the point behind this statement, that I 

 find it difficult to refrain from using the word " soul." 



If, however, such a view is considered, it must be said 

 that there is no evidence that any individual physico- 

 chemical phenomenon is developed within the brain that is 

 not developed within other parts of the nervous system, and 

 in a more confused manner, indeed, within the limits of 

 every living cell. It is some special arrangement of 

 dynamic states that must be held to form the special 

 characteristic of the waking brain, and it should be possible 

 in time to define the peculiarities of those special arrange- 

 ments whereby we are assuming that the mind is, so to 

 speak, caught. 



It is true, too, that there are great difficulties offered to 

 the expanded presentation of a statement which suggests a 

 mysterious influence provocative of mind as possessed 

 apparently of something of the nature of a physical force, 

 since it is held to be constrained in certain peculiarities of 

 physical environment to behave in a special way. It is, 

 indeed, almost clear that this influence must be held to 

 affect those physical surroundings, since there is little 

 doubt that mind, per se, affects human conduct and animal 

 behaviour, just as it is impossible to conceive mind, where 

 present, as exerting no influence in natural selection. This, 

 although the risks of the environment must always play 

 the greater part in natural selection, and the influence of 

 the mind be conceived as bnly secondarily affecting the 

 organism through the intervention of the nervous system, 

 or through mechanisms that are substituted for that system. 

 Admitting these facts, we should in this case be obliged to 

 regard mind resonating amongst the distributed dynamic 

 states of the brain as influencing them in a way that might 

 possibly be demonstrable in any physical apparatus closely 

 imitating those states and their distribution. 



Then, again, one of the main objections to a suggestion 

 of this kind is that the condition might involve a trans- 

 formation of energy which should have been discovered as 

 an otherwise unexplainable quantity in the energy equa- 

 tions of the body. There may, however, be no real 

 necessity to conclude that any transference of energv would 

 be involved in such a process. The distribution of dynamic 

 states in the central rervous system which are suggested 

 as playing the part of resonators is, as I have already 

 related, a distribution of opposite states. If we consider 

 how these opposite states, excitation and inhibition, are 

 arranged in any given case, it is seen that the installation 

 of an equal number of excitations where inhibitions were 

 present, and of inhibitions where excitations were present, 

 will give rise to a new pattern of a very different mean- 

 ing. Now such a change in the distribution of states 

 might entail either no more than the transmission of 

 nervous impulses, a process in which exceedingly small 

 quantities of energy are dissipated, or, indeed, an actual 

 cessation in the transmission of certain nervous impulses, 

 since it is one of the curious features in these states that 

 the one tends to recoil into the other. We might, indeed, 

 make the assumption that an alteration in the setting of 

 the instrument, such as was attended with a change in 

 consciousness, was always attended by this cessation of 

 nervous impulses, so that a brilliant display of mind might 

 be associated with no increase in the transformation of 

 physical energy, but actually with a diminution in the 

 transformation. Under cover of such an assumption it 

 might be held that this mysterious influence of which I 

 have spoken absorbed instead of contributing energy to 

 the system, or that it diverted energy without loss from 

 one part of the system to another. 



Now, in my opinion, there is no one at the present time 

 who is in a position to discuss the energy transformation 

 of the central nervous system. Further, there is certainly 

 no one capable of dealing with such peculiarities as might 

 arise in the energy transformation of that part of it, the 

 brain, which is associated with the mind. There are many 

 points to be cleared up, as, for instance, the extraordinary 

 relationship of the central nervous system to the general 

 muscular system, upon which I might be allowed for a 

 moment to dwell. The fibres of skeletal muscle form the 

 largest site of energy transformation from the oxidation 

 of food or fuel, a site in which apparently no such trans- 

 formation takes place without a coincident exhibition of 

 characteristic muscle function and the performance of some 

 NO. 2185, VOL. 87] 



mechanical work, and are dominated in this transforma- 

 tion by impulses discharged from the ventral portion of 

 the central nervous system. This exhibition of function 

 is invariably the cause of a dispatch of nervous impulses 

 into the central nervous system again, along the nerve- 

 fibres passing into its dorsal portion. Now, since the 

 energy set free in muscle is out of all proportion to the 

 small sum of energy transmitted from the nervous system, 

 it is capable, amongst other things, of dispatching back 

 again to the central nervous system a compensating or 

 even an additional sum of energy. The musculature might 

 then be supposed to reinforce the nervous system. Until 

 such points are given their due importance, it would be 

 ridiculous to dogmatise about the energy equations of the 

 central nervous system, and to discuss the amount of 

 energy expended in the performance of movements, or 

 stored in the absence of movements, within this system. 



I will not labour these points, upon which I can throw 

 no light, but put forward this expression of belief rather 

 than opinion to explain an attitude revealed in the re- 

 mainder of this address, and not as based on evidence or 

 in any way a statement of demonstrated or demonstrable 

 fact. The essential point for the moment is this — that 

 there is some loophole for the view that mind is not 

 directly associated with life or living matter, but only in- 

 directly with certain dispositions of dynamic state that are 

 sometimes present within certain parts of it. It is a point 

 of view not without interest to physiology, since it would 

 leave that science free to consider all phenomena present 

 in such forms of life and living matter as carry no sugges- 

 tion of an association with mind, as nothing more or less 

 than physico-chemical phenomena, which, when thoroughly 

 investigated, would be completely translatable into scien- 

 tific terms. Then, too, when there is evidence of mind, the 

 view is that it represents a force acting from without upon 

 what is still no more than matter involved in certain 

 chemical and physical states. Incidents of function would, 

 in such a view, pass straightway into the realms of 

 physical and organic chemistry, requiring special methods 

 of investigation alone, because of the localisation of pro- 

 cesses and punctate states in minute microscopical parts 

 not readily removed from their surroundings into selected 

 experimental surroundings of the same value. 



We are at liberty, then, to deal with this series of 

 physico-chemical experiments, boldly giving each observed 

 difference in circumstance a possible importance in the 

 determination of observed differences of character, and each 

 difference in character a probable explanation in terms of 

 simple differences in circumstance ; we may boldly consider 

 the causation of variations, and use the term " natural 

 selection " as equivalent to the physico-chemical limits to 

 the successful maintenance of each experiment. Let us, 

 for example, begin with the blood. 



It is at once legitimate, in the first place, to ask how 

 this blood tissue has arisen from variation in the chemical 

 reactions of nuclear material. The argument runs that 

 some ascertainable cause must have produced a material 

 variation which has been preserved by natural selection, 

 and quite probably, too, by the persistence of the cause 

 over some long period in the history of nuclear material. 

 There is no harm for the moment in surveying causes and 

 temporarily fixing upon one that seems to possess greater 

 appropriateness than any other. Therefore I suggest that 

 we take this main characteristic of nuclear material in the 

 blood tissue, that it is engaged in the production of a 

 pigment, and that the most efficient cause determining 

 pigment production is the action of light. Remembering 

 that we are probably dealing with nuclear matter in 

 general from which this particular material has been split 

 off and set aside by subsequent causes, we can admit this 

 postulate. The pigment-forming propensity of blood is 

 thus taken as probably due to the initial action of light 

 upon nuclear material placed near the surface of the body, 

 and there exposed to the action of light. 



Our next step is to discover any probable fact which, 

 favoured by natural selection, might drive into the interior 

 of the body nuclear matter that had been so modified by 

 light that it persisted in the formation of pigment ; in 

 other words, Why should any pigment-forming reaction 

 ever be removed from the direct influence of light, and a 

 valuable transformer of radiant energy be thus driven into 



