The Vegetal Operations

a) Nutrition

The first operation of the plant is the taking and absorbing of food. This operation is called nutrition, which, literally, means the act of nourishing or feeding. We may define nutrition as “a vital operation by which a living body transforms suitable extraneous matter into its own substance.”

Nutrition is a vital operation. It is the activity of a living body; it originates in the living body, and is exercised by and for the living body. Thus, like all vital operations, it is essentially immanent in character, although it is exercised and manifested by actions that are transient.

Nutrition involves the preliminary functions of taking in the food (by roots, leaves, etc.), digesting the food taken in (i.e., preparing it chemically for assimilation), absorbing the digested food and circulating it through the living body to places where it is required. Then comes nutrition properly so-called, and the food (which has been taken, digested, absorbed, circulated) is assimilated and made one with the actual cell-structure of the living body. The materials taken as food are seldom composed entirely of nutritive elements; some unsuitable portions must be cast off again; besides, the discarded, worn-out, and replaced elements of the organism must be cleared away. This is effected by the function called elimination. In addition to the functions named, nutrition involves the secreting of certain juices required for the proper discharge of its processes.

The first operation of the plant, and indeed of any living body, is nutrition. We have seen that bodily life is manifested in grades, and therefore the functions of the lowest grade are common to all grades. The nutritive operation has functions of a somewhat more elaborate character in animals and men than it manifests in plants. To avoid repeating much of the present study in later chapters, it is well to append here an outline-sketch of nutrition as it is exercised in the more perfect animals and in man, and to mention the organs and functions involved in the process:

1. Taking food. Organ: the mouth. Function: mastication; insalivation.

2. Digestion. Organ: stomach and intestine. Function: breaking up and commingling of the food by the mechanical action of the stomach. Mixing in of the gastric juice (secreted by gastric glands) which turns the food in the stomach into a chemical mixture called chyme. Turning of the chyme into the intestine, where the pancreatic juice, bile, and intestine fluids transform it into a chemical mixture called chyle.

3. Absorption. Organ: intestine. Function: the true food-elements of chyle are taken into the blood,—passing through the intestinal walls by a process called endosmosis,—and are carried, partly by veins and partly by lymphatic vessels, to the heart, and thence, by the pulmonary artery, to the lungs, where the blood is perfected and purified.

4. Respiration. Organ: the lungs. Function: the blood,—a liquid which carries needed elements to all parts of the organism, and carries away used and discarded matter and harmful by-products of organic action,—is taken through the pulmonary artery (or *lung-*artery) to the lungs, where an intake of oxygen, and the discharge of its freight of carbonic-acid gas (carbon dioxide) purifies it. When laden with carbon dioxide, the blood is very dark in color; when purified, it is bright red. The action of the lungs is partly mechanical (bellows-like action of breathing) and partly physico-chemical (mingling of the oxygen in the inbreathed air with the elements of the blood; elimination of carbon dioxide).

5. Circulation. Organs: heart; arteries; veins; capillary vessels; lymphatic vessels. Function: the heart, a hollow muscle of two parts, acts like a double pump: one channel of its pressure carries the dark used blood (and its freight of new elements from food digested and absorbed) to the lungs; the other carries the red blood through the arteries to build up and maintain the organism and support its connatural operations. Arteries carry the red blood to the organs (but the pulmonary artery carries the dark blood to the lungs); veins carry the used blood from organs back to heart (but the pulmonary veins carry red blood from lungs to heart); capillary vessels exist in great number at the terminations of the arteries and connect the arteries with the veins; lymphatic vessels (so named from lymph, a colorless liquid which helps bring absorbed food elements to the heart) constitute a sort of parallel system with the veins and arteries and connect with the system of veins not far from the heart.—It will be noticed that the circulation of the blood has two “circuits”: one carries the blood from heart to organs and back to heart, and this is the major circuit; it is known as systemic circulation. The other circuit carries the blood from heart to lungs and back to heart; this minor circuit is called pulmonary circulation,—a term which derives from the Latin pulmones “lungs.”

6. Assimilation. Organs: all the various parts of the organism which take from the blood the elements they need and transform these into their own substance. Function: the transforming of required elements found in the blood into the substance of the acting organ; the deassimilation or unloading into the blood of waste matter by the various organs.

7. Secretion and Excretion. Organs: glands. Function: the secreting glands produce fluids,—drawing the materials for these from the blood,—which the living body requires for positive organic functions. Such, for example, are the salivary, the gastric, the intestinal glands, the pancreas, the liver. The excreting glands separate out a product that is to be eliminated or cast off from the body, either as simple waste matter, or as a cleanser and wash for organic parts. Such, for example, are the kidneys, the sweat-glands, the lachrymal glands (or tear-glands).

b) Growth

The direct effect of nutrition is the preservation and development of the organism. As the living body develops, it increases in size; it grows. Growth continues, in normal circumstances, until the organism has attained a state of maturity or complete development. Thereafter, the effect of nutrition is to maintain the mature body in a properly functioning condition until its term of operation is finished.

It is by means of nutrition, and as a result of nutrition, that the body grows. Yet growth is a vital operation really distinct from nutrition. Growth may be defined as “a vital operation whereby a living body, by taking nourishment, increases its quantity and tends to attain its proper size.”

Growth is a vital operation; it is immanent in character, although it necessarily has outer effects which are transient in relation to surrounding bodies.

Every species of living body (that is, every distinct natural class, the members of which do not breed indefinitely with members of another class) has a definite morphological type (a term derived from the Greek morphe “form,” which, in the present use, indicates structure and shape). There is, in every species, a range of size, from minimum to maximum, within the bounds of which bodies of that species are always found.

The basic element of every living body,—plant, animal, human,—is the cell. The cell is a microscopic organism, usually somewhat rounded in shape, which contains protoplasm and a nucleus. Protoplasm (from Greek protos “first,” and plasma “a thing formed”) is a jelly-like material technically described as “a viscid, contractile, semiliquid, somewhat granular substance, which forms the larger portion of the cell.” The nucleus (Latin nucleus “kernel”) is a body embedded in the cell; it is the main organ of the cell; it is the organ which serves the cell, first and foremost, in the discharge of its functions. The cell draws in food, by a process of osmosis, from surrounding substances, for the cell, being an organism or living body, manifests the operation of nutrition. Further, the cell grows, and when it has attained a suitable size, it is multiplied, each of the resultant cells being like the original cell. The growth and multiplication of cells continues; different cells of the same nature are united in tissues. From tissues the organs are built up, and the balanced union of organs makes a finished living body of the type from which the original cell (or parent-cell) was derived. Thus, the growth and multiplication of cells,—in accordance with the vital drive resident in the original cell, which makes for the upbuilding of a definite morphological type,—accounts for the growth of living bodies.

It is to be noticed that the cell itself is a living body or organism. Except, however, in the one-celled animals (unicellular animals), the cell tends to develop into a larger and more complex organism of a definite kind (or morphological type). Both the cell itself and the body which results from its development and multiplication are organisms. It is more usual, however, to employ the term organism for the completed body,—that is, for the body completely formed, although not necessarily completely developed to maturity.

c) Generation

By the term generation we mean, in this present study, an active vital operation. We mean the operation of propagating, of reproducing. Generation is an operation found in all types of living bodies. It may be defined as “a vital operation whereby a living body produces, out of its own substance, another living body of the same nature.”

The definition does not mean that the new living body (the offspring) comes completely formed out of the substance of the parent-body. It usually comes in the form of a seed or germ which is capable of developing (and tends to develop) into a complete living body of the same nature and morphological type as the parent-body. In plants and in the more imperfect animals, generation sometimes takes place by the budding out of offspring already formed, or by the mere severing of a suitable part from the parent body,—such, for example, as a branch, or twig, or root, capable of sustaining life and exercising vital operations as an independent individual plant. In most cases, however, generation comes about by the development of a cell which contains elements drawn from a male and a female body of the same specific nature. This seed-cell grows and develops in the manner already described; it is the source of all the cells, however different, that go into the making of the new organism or offspring.

Sometimes the original cell (containing the male and female elements) develops into the organism outside the confines of the parent-body. Thus seeds of plants are sown in the fertile earth so that the organism may develop. Thus the eggs of certain types of animals are hatched outside the parent-body. Sometimes the original cell (seed or germ) is developed within the female body which contributed, with the male, to its formation; and then the developed offspring is born into its separate existence. A point to be remembered is this: generation is not birth; the operation called generation is exercised when the male and female elements conjoin to form an active cell which thereupon begins to develop; the moment of this joining is called the moment of conception; and the moment of conception sees the emergence of a new life, a new and individual organism, which, in the case of human beings, has then and thenceforth the right to life.

d) Vegetal Powers

Wherever we find an operation we find a principle for that operation. A principle, it will be recalled, is that from which anything takes its rise in any manner whatever. Now, we know that the living body is the principle of its operations; more precisely, we know that the soul or life-principle is the principle of the vital operations. That is to say, the soul is the first principle of such operations. But there is need to discern the immediate or proximate principles whence arise the specific operations of living bodies. We find that there are certain powers, distinct one from another, and all of them distinct from the substance of the living body, which constitute the active equipment of the organism. These powers,—notably in the higher types of animals and in men,—are sometimes called faculties, a term which comes from the Latin facere “to make” or “to do.” Powers or faculties are capacities possessed by the living body for doing something, that is, for exercising the operations proper to its nature.

In plants, and in all living bodies,—since all organisms possess the basic plant-grade of life,—there are three distinct vegetal powers or plant faculties, and these are the respective proximate principles of nutrition, growth, and generation. We call these proximate principles of plant-operation: the nutritive power, the augmentative or growing power, and the generative or reproducing power.

The first power manifested by the plant is the nutritive power. The most noble or excellent is the generative power. An organism is said to have reached full development or perfection when it is capable of reproducing its kind.

Summary Of The Article

This Article has given us a knowledge of the connatural operations proper to plants, and,—since all living bodies share the vegetal grade of life,—to organisms generally. We have defined nutrition, and have discussed the functions incidental to this operation, listing those peculiar to animal and human organisms in addition to those found in plants. We have defined growth, and have indicated the development and multiplication of the cell as the root-source of growth in living bodies. We have defined generation, which is the reproductive operation in living bodies; we have indicated the manner in which new organisms come into existence. Finally, we have learned that the respective proximate principles of the vegetal operations are three powers or faculties proper to organisms (viz., the nutritive, the growing, and the generative powers); we have learned that these three powers are distinct from one another, and also distinct from the substance of the living body which possesses them.