The commonwealth of cells

by H. G. F. Spurrell

Death may begin in many ways. The loss of some organs will bring death only after a considerable time, while the failure of others disturbs its economy fatally, and causes an almost immediate cessation of the vital functions. Any interference with the normal conditions of the brain, heart, or lungs is very dangerous, and it is injury or disease of one of the three which puts an end to most men’s troubles. If the brain weakens so that it no longer keeps the heart beating or the muscles, which fill and empty the lungs, to their duties, the body, for obvious reasons, can no longer keep up the cycle of changes we call life. On the other hand, if the lungs cannot oxidize the blood, or the heart drive fresh pabulum to the brain, that organ collapses immediately, and, if a stream of pure blood is not quickly restored to it, dies. No return of the circulation can then restore it; the death of the rest of the animal must follow.

Being the most delicate, the cells of the central nervous system usually die first, and we then say that the man is dead. So the body may be, but much of the protoplasm of which it is composed—whole organs, in fact—remains alive; the muscles will respond to electrical stimulation, and in case some people may dispute that this is a sign of life, if pieces of his skin be removed and grafted into another person, they will grow there, produce hair, and become, in fact, a part of the new body. This they could not possibly do if they were dead; we cannot endow inanimate matter with life.

As death creeps on over the tissues, the leucocytes die, and in doing so form a ferment which solidifies one of the proteids dissolved in the blood, so that the familiar clotting takes place. By a similar process certain constituents of the muscles are also clotted, the muscles stiffening and passing into what is technically, but also pretty generally, known as rigor mortis. Rigor is said to set in soon after death if the body is kept in a warm place, or if death has been preceded by violent exercise; but death in this instance means only the death of the body. It is at the precise moment that a muscle fibre dies that it passes into rigor. By keeping it cool, so that the processes of life may go on slowly, especially if it be in a healthy condition, its death may be deferred for hours; while, on the other hand, at the end of a severe and protracted battle, exhausted soldiers sometimes die instantaneously on being shot, and are found fixed in the position in which the fatal bullet found them—on their knees, with gun to shoulder, in the act of firing.

But if the manner of death is not to be lightly dealt with, its causes are still more obscure. It seems natural enough that people should be killed by violence or by diseases with an external or septic origin, or even by one particular organ wearing out and involving the whole body in the fate of its part. But why should people die of old age? Why should their vitality ebb till they quietly go out? Life is a mechanical cycle of changes. For a time even after it has stopped growing, the body replaces what it wastes, and keeps itself in a condition of equilibrium. Why, then, without any apparent external cause, does it, after a more or less circumscribed period, enter into a decline? And, finally, could we, by taking the proper precautions, delay or prevent old age and death?

In the first place, regarding protoplasm as a chemical structure, why, if kept under favourable conditions, should it ever break down? We have no reason to suppose that it need. It is hard to see how the minute animals, consisting of only one cell, can die of old age, provided that no injurious influence be brought to bear upon them. When an individual has grown to a certain size, it divides in two, and each enters upon life afresh. Why, therefore, should not all the cells of the body continue to renew their youth?

The reason why the body can only last a certain time, in spite of the many quacks with recipes for immortality—recipes including such items as the avoidance of all trouble, worry, or work—must remain a secret until we know the chemical basis of life. It seems to lie in the cell. If a unicellular organism, as described above, be placed in a vessel of sterilized water and left to live alone under otherwise ideal conditions, it will start dividing and multiplying, as though it meant to reproduce itself indefinitely. After a time, however, the shoal begins to deteriorate; each successive generation is feebler than the last, and eventually all die. If, however, before this happens one of the effete cells be placed in another vessel with a similar individual derived from a different ancestor, the two will fuse and form a single fresh animal with entirely restored vigour, ready to multiply to the same extent as either of its original ancestors. A few individuals of a different stock will in this way revivify the whole brood.

There is, therefore, evidently something in the cell which wears out after it has divided a certain number of times—something which must be restored by blending with cells of another strain. What this is we do not know, and perhaps never shall. The most we know is that it seems to be something inherent in the nucleus, not the main body of protoplasm of the cell, for some unicellular animals do not fuse, under the circumstances related above, but exchange only pieces of their nuclei, and yet derive the advantages of mutually increased vitality. But if we apply the fact to our conception of the body as a vast colony of cells with a common origin, we find that it has an important bearing upon the duration of its life.

The single eggcell which gave rise to our schematic embryo in [Diagram 3, Fig. 1], was formed by the fusion of two cells shed by two distinct animals. How this one cell grows and multiplies by division is roughly shown in the diagram and those immediately following it; but though the cells do not separate, but hang together and form a body, it is obvious that the colony only amounts to a shoal of unicellular organisms, like that described above as growing weaker with each successive division unless blended with individuals of a different stock. This cannot be done in the body; what would become of our individuality even if such a thing were possible? The body can help to give rise to new bodies, but its own tissues must wear out, and when the colony of cells is exhausted it must die. Careful diet and regular habits, the minimum of wear and tear, may enable the body to run its full term; but they cannot lengthen the lease of life.

So far only can the physiologist take us. Physiology may teach us how to develop our powers and economize our strength; it is already beginning to convert medicine from an art into a science; it will, it is to be hoped, shortly work a revolution in our at present barbarous ideas of how to rear and educate children; it may, in short, teach us how to make the very most of life and die easily; but not until, if ever, it understands the physical basis of life, and perhaps not even then, will it be likely to succeed in prolonging a man’s days much beyond the traditional fourscore years.