And there has been advocated still another view in order to amplify the sphere of adaptation: all individual morphogenesis, not only restitution, is adaptation, it has been said. In its strictest form such an opinion of course would simply be nonsense: even specific adaptive structures, such as those of bones, we have seen to originate in ontogeny previous to all specific functions, though for the help of them, to say nothing of the processes of the mere outlining of organisation during cleavage and gastrulation. But they are “inherited” adaptations, it has been answered to such objections. To this remark we shall reply in another chapter. It is enough to state at present that there is a certain kind of, so to speak, architectonic morphogenesis, both typical and restitutive, previous to specific functioning altogether.
If now we try to resume the most general results from the whole field of morphological adaptations, with the special purpose of obtaining new material for our further philosophical analysis, we have reluctantly to confess that, at present at least, it does not seem possible to gather any new real proof of life-autonomy, of “vitalism,” from these facts, though of course also no proof against it.
We have stated that there is in every case of both our types of adaptive events a correspondence between the degree of the factor to which adaptation occurs, and the degree of the adaptive effect. We here may speak of an answering between cause and effect with regard to adaptation, and so perhaps it may seem as if the concept of an “answering reaction” (“Antwortsreaktion”), which was introduced into science by Goltz[87] and which is to play a great part in our discussions of next summer, may come into account: but in our present cases “answering” only exists between a simple cause and a simple effect and relates almost only to quantity and locality. There is therefore lacking the most important feature, which, as will be seen, would have made the new concept of value.
We only, I believe, can state the fact that there are relations between morphogenetic causes and effects which are adaptations, that functional disturbances or changes are followed by single histogenetic reactions from the organism, which are compensations of its disturbed or changed functional state. We are speaking of facts here, of very strange ones indeed. But I feel unable to formulate a real proof against all sorts of mechanism out of these facts: there might be a machine, to which all is due in a pre-established way. Of course we should hardly regard such a machine as very probable, after we have seen that it cannot exist in other fields of morphogenesis. But we are searching for a new and independent proof; and that is indeed not to be found here.[88]
At present it must be taken as one of the fundamental facts of the organogenetic harmony, that the cells of functioning tissues do possess the faculty of reacting to factors which have changed the state of functioning, in a way which normalises this state histologically. And it is a fact also that even cells, which are not yet functioning but are in the so-called embryonic or indifferent condition contributing to the physiological completion of the tissue, react to factors embracing new functional conditions of the whole in a manner which leads to an adaptation of that whole to those conditions.
This is a very important point in almost all morphological adaptation, whether corresponding to functional changes from without or resulting from the very nature of functioning. In fact, such cells as have already finished their histogenesis are, as a rule, only capable of changing their size adaptively, but are not able to divide into daughter-cells or to change their histological qualities fundamentally; in technical terms, they can only assist “hypertrophy” but not “hyperplasia.” Any adaptive change of a tissue therefore, that implies an increase in the number of cellular elements or a real process of histogenesis, has to start from “indifferent” cells, that is to say, cells that are not yet functioning in the form that is typical of the tissue in question; and, strange to say, these “embryonic” cells—i.e. the “cambium” in higher plants and many kinds of cells in animals—can do what the functional state requires. It is to be hoped that future investigations will lay a greater stress upon this very important feature of all adaptation.
2. Physiological Adaptation[89]
It is but a step from morphological adaptations to adaptations in physiology proper. The only difference between regulations of the first type and those which occur in mere functioning is, that the resulting products of the regulation are of definite shape and therefore distinctly visible in the first case, while they are not distinctly visible as formed materials but are merely marked by changes in chemical or physical composition in the latter.
Metabolism, it must never be forgotten, is the general scheme within which all the processes of life in a given living organism go on; but metabolism means nothing else, at least if we use the word in its descriptive and unpretentious meaning, than change in the physical or chemical characteristics of the single constituents of that organism. In saying this, we affirm nothing about the physical or chemical nature of the actual processes leading to those physical or chemical characteristics, and by no means are these “processes” a priori regarded as being physical or chemical themselves: indeed, we have learned that in one large field, in the differentiation of our harmonious systems they certainly are not. Now, if the metabolism does not end in any change of visible form, then true physiological processes, or more particularly physiological regulations, are going on before us. But we are dealing with morphogenetic events or regulations, if the result of metabolism is marked by any change in the constituents of form. This however may depend on rather secondary differences as to the nature of regulation itself, and any kind of metabolism may really be of the regulatory type, whether we actually see its result as a constituent of form, e.g. owing to the production of some insoluble compound, or whether we do not.