Johann Christian Reil (1759-1813)

On the Vital Force

Archiv für die Physiologie 1, 8 (1796) [as excerpted and translated in Mikulás Teich, A Documentary History of Biochemistry, 1770-1940 (Rutherford, NJ: Fairleigh Dickinson University Press, 1992)]


That we do not find in inanimate nature phenomena belonging to those of the animate world depends on the specific kind of the organic material which is not found in inanimate nature. Can we, indeed, on this account deny to all others special properties, which a certain kind of matter lacks? Must we, therefore, deduce the magnetic property of iron from something other than matter because we observe no magnetic phenomena in tin, in stone and in wood?


The material of animate nature is markedly different from the material of inanimate nature. The vegetable and animal matter have a certain similarity and constituents which are common to both. Therefore we perceive also in the animal and plant phenomena a certain specific and unmistakable similarity. Therefore we include, and indeed rightly, animals and plants under the common nature of organic beings and separate them from inanimate nature. But although the composition and form of the animal and vegetable matter has similarity it is still not the same.[1] Therefore the plants and also the animals display each its specific manifestations, by which they distinguish themselves.

Why are the phenomena of animal bodies so necessarily bound to a certain composition and form of matter? If we moisten, dry, stretch, relax, compress the animal bodies, in short alter the physical condition of the matter, then immediately is also the tone of the vital force altered. A change of the matter causes a change in all its forces and we have no means, as many a physician may well think, which affect only the vital forces and others which affect only the inanimate forces. Why also do stones, Vaucanson's automats and Kempelen's chessplayer not live, if nothing further belongs to life than that one implants a soul or a vital spirit into inanimate matter? Why has a man never begot a marrow, why has a donkey never predicted anything and why has the oak never moved its branches of its own free will, as the animal its limbs?

The composition of the animal matter extending from the simplest elements to the most perfect organs is highly specific. We find everywhere different elements, a different proportion of their combination and several orders of simple and composite components. Already through mere senses we perceive that each organ has its own composition, and that the same organ always has the same composition. How characteristic is the composition of matter in muscle flesh, in nerve medulla, cell tissue, viscera, bones? How do they differ from one another? A nerve which works as a nerve has its own and never another matter. Why this stability in the composition of matter? Why does one always find in the nerve tubes nerve medulla, never jelly or anything else?


The organic matter is indeed as much specific in the organic realm and never is to be met in inanimate nature. But the very beginnings of the same lie certainly already totally on hand in the womb of the inanimate nature.


One has always cherished the opinion that in nature a certain subtle principle comprises the proximate cause of its phenomena ... especially was this subtle principle assumed to be the basic source of the phenomena in the organic nature.


Yet I wish finally to warn against an error, namely that one must not believe that these subtle substances are alone the force or at least the substrate or organic beings. The foundation of life lies in matter as a whole, in the composition and form of all that which is visible and invisible. The subtle matter can as little produce life by itself as can the coarse matter alone. All that is must be there, if from it the final result: life, is to emerge ...

In the way the composition and mixture of the animal substance is specific and perfect, its form and development is just as specific and perfect. It is a wondrously artistic construction, within the animal body, in its principle simple and in its connections most varied that is so superior to the structure of the inanimate nature and the works of art. Not only the whole body or its coarse components, but even its smallest parts are machines; everything, down to the smallest fibre, dissolves itself into nothing but purposefully formed bodies. The whole body consists of several large components; each component again [consists] of muscles, vessels, nerves; the muscle again of skin, fibres, vessels. What ingenious and composite mechanics! How many stages and arrangements of the same! How far has anatomy reached in its analysis and works of art and that of inanimate nature! Here is only the whole a machine and the parts of the whole are natural bodies without purposeful development. To the regular mechanism of the animal body there also belongs both the coarse and the fine tissues of the fibres, the articulations of the large parts, the proportion of the size of the parts to one another, the number of the same etc. Through the union of these countless organs, which by different stages combine together into a whole machine there are equally composite forces communicated to it. Through this arrangement it is also capable of manifold manifestations, which in inanimate nature are not possible.

To the formation of the substance of animate beings we have given a specific name organization on account of its excellent perfectness. Organ and organization is thus formation and structure of animate bodies ...

It would be advantageous for theoretical and practical medicine if we could analyse the different kinds of degrees of organization, if we could reduce their most complex tissues to their most simple elements and if we were able to follow them from the original most elemental organ to the most complex animal organs. We would then be able, more happily, to analyse many phenomena and to reduce them more accurately to their principles. Simple organs which were formed out of homogeneous material must indeed produce the same phenomena; in contrast the composite organs are the embodiment of the forces of the simpler organs behaving as the simpler organs behave, from which they are built up.


All phenomena in the corporeal world are results of a definite form and composition of matter ...

The relation of the phenomena to the properties of matter through which they are generated I name force. Force can thus be considered general, special, and individual in he way that the relations of the effects to the causes, and the phenomena to the properties of matter, may be thought about. Force is thus something inseparable from matter, a property of the same through which it brings forth phenomena.

Force is a subjective concept, the form in which we think of the relation between cause and effect. If it were possible for us to think at the same time clearly of each body as it is, of the nature of all its elements and their combination, and of their composition and their form, then we would not need the concept of force, which gives occasion for quite a number of erroneous conclusions. In the case of phenomena not related to the senses, for instance the ability to think, we are inclined to look for the force in the substrate of the senses or in a metaphysical substrate, and we tend to invest [sic; perhaps "invent" is appropriate?--CJG] such a substrate if we cannot demonstrate it. With material things we often try to perceive the cause of their manifestations in still other things than those which we have before us and perceive with the senses. We put in the muscle additionally an irritable substance, in the nerve additionally nerve spirit and regard these things as the characteristic substrate of the force or as the final principle of animal phenomena. We are inclined to think of the force as something different from matter and to regard matter as the vehicle of the force, although its manifestations are inseparable from it and are results of its properties. Matter is nothing other than a force, its accidents are its effects, its being is action, and its specific being is to act in a specific way. Alkali and acid combine to give a neutral salt, because this is the property of these things which cannot be separated from them. Besides the alkali and the acid there is no third thing which brings about this combination. Common salt grows into cubic crystals because it is common salt, which as a specific kind of matter is wont to grow in this way.

The forces, or the partnership which finds place between the phenomena and the properties of matter, we define subjectively according to the more or less general nature of the phenomena. According to this definition of the concept force, the word[2]

  1. Physical force indicates: the most general manifestations of matter and its relation to more general properties that we meet both in inanimate and animate nature.[3]
  2. Vital force[4] indicates the relation of more individualized phenomena to a special kind of matter which we encounter only in living nature with plants and animals. The most general attribute of this particular kind of matter is a special kind of crystallization. Besides, we cannot offer any genetic definition of this force as long as chemistry has not made known to us more exactly the elements of organic matter and their properties. Until then it will be impossible to set a definite boundary to the different realms of nature. Are the phenomena of life effects the sum total of properties, which are met with in the animal matter, or is there a single matter on which alone depend the phenomena of life, as the expansibility of all natural bodies depends on caloric? The latter view appears not probable to me, because we never meet in nature a simple matter which has life, but find it always only in the known combination with visible substances, because life expresses itself through so very different phenomena; and finally because through alteration of the visible matter, or by addition of different substances, electricity, heat, oxygen, opium, etc. we can now raise, now lower the vital force.
  3. Vegetative force and its product plant life, is a property of a special matter of which plants consist.
  4. Animal force indicates the property of a more individualized matter which we meet in the animal kingdom, characterized by a specific phenomenon, namely muscular movement. One can divide the animal force according to the special modifications of matter in muscle and nerves again into sensitive force and motive force, although this division is not logically correct. We can think of the forces as individualized as often as matter may be individualized. Only one must imagine in this way nothing further than another chemically combined and formed animal matter, which thus gives rise also to other phenomena.
  5. Finally remains the faculty of reasoning which is peculiar only to man.

If we go in this way from the most general phenomena of bodies, by degrees, to their special manifestations: then we come at last to phenomena which can only find place in an individual body, indeed only in a single part of the same; in the brain, in the nerves, and so on.

The forces of the human body are thus properties of its matter, and its special forces are results of its specific matter. The phenomena of matter are as different as are its properties and the relation between phenomena and properties as manifold as the properties of matter are manifold. However much these relations can be thought of as varied, the concept of force is equally as varied.


The physical, chemical and mechanical forces of animal bodies, it is said, are subordinated to the vital force, at the same time bound by it and are only freed from this subordination by the death of the animal and again set in authority.[5] But such authority and subordination actually cannot be imagined in nature, but everything works in it according to eternal and immutable laws. Our subjective concepts, which we carry over into nature, not seldom deceive the mind of stupid human beings and hand them, instead of reality, a plaything. In nature one finds no separation of the forces, no universality, authority or subordination, but the bodies are concrete and bring forth their phenomena according to their matter. In the muscle fibre matter, as it is, produces all its phenomena; its matter is heavy, it coheres, it is extensible, elastic, slippery, soft, it has special chemical properties, it is sensitive to stimulus, it contracts on stimulation. These different phenomena of the muscle fibre we must not seek, perhaps, in special principles of the same, but their matter, such as it is, is heavy, irritable, etc., and contains the cause of all its phenomena. A matter which is heavy remains, so long as it is this matter, unaltered in its heaviness and no subordination can suppress the expressions of the heaviness. Suppose also it as bound also with another matter which had just as much absolute lightness as it possessed of heaviness, then our senses would indeed be deceived but thereby the effect of heavy matter would not be nullified.

Also it is said of the chemical laws of affinity that they are subordinated to the vital force and rescinded by it. But no law can be rescinded in nature, so long as the conditions, under which it operates, last. If the conditions alter then the law is rescinded, not in nature but in our mind. The animal bodies consist of a specific matter, thus have also their own laws of affinity, as also the bodies of inanimate nature have their own. Putrefaction is brought up as an example and it is contended that it is a natural law of animal substances that they putrefy. The law, however, is subordinated to life. But putrefaction is only a property of the inanimate and not of the animate animal matter. With loss of life some or other component of animal matter, in presence of which no putrefaction could occur, will be eliminated and removed. After the elimination of this substance the properties of the rest of the matter are altered, including its chemical laws. Thus also no dead flesh putrefies so long as one adds alcohol; no barley ferments as long as one of its components, gluten, is not removed through germination.[6]

[1]Grens Chemie, pt II ¶1395. p. 275 (second ed)

[2]I believe that we would give the least opportunity for misinterpretation if, instead of force we used the word property of matter. We would then in physiology first look at the general phenomena which organic matter has in common with inanimate nature, then we would consider those of its properties which are indeed specific to it, but belong to the whole animate kingdom of nature, then we would pass over to the special phenomena of the vegetable and animal matter. Regarding the animal matter we would consider its own kind of irritability and its modifications, nerve irritability, muscle irritability, gland irritability, etc., according to the differences in the composition of the matter in the special kinds of organ.

[3]The words physical, chemical force, etc. appear already to show that we have not always associated with them the correct concepts. Everything in the corporeal world acts physically: also the living organic matter and all forces can be traced in the end altogether to the differences in elements and to their single universal property, affinity.

[4]I have named the force of matter which characterizes the plant and animal kingdom the vital force and taken the word vital in its widest meaning. Perhaps others find the word organic force more suitable. I have not chosen it, however, because organization in ordinary usage denotes the formation of animate beings. But words are arbitrary signs of our concepts and it depends only how precisely we define the concept which we associate with a certain word.

[5]Schmidt, Empirische Psychologie Jena 1791, p. 413.

[6]I can therefore not assent to the definition of the vital force which Humboldt gives (in his Aphorismen aus der chemischen Physiologies der Pflanzen, Leipzig 1794. pp. 1-9). That inner force, he says, which loosens the bonds of chemical affinity and hinders the free combination of the elements in the body, we call vital force.

Back to the list of selected historical papers.
Back to the top of Classic Chemistry.