Imágenes de páginas




THE BEGINNINGS OF LIFE. IN the ebb and flow of thought so characteristic

T of our modern intellectual life, one idea has many times gained, and as often lost, ground. From the days of Galileo to the present, during the centuries which have elapsed since the gift of its new vision had been bestowed upon the world by the blind Florentine, the doubt has now and again found voice, whether even Divine love and care can be commensurate with Divine power. The infinite reaches of space, revealed or suggested by the telescope, exhausts our capacity for belief. We stagger before the thought of an Intelligence which can and does fill every portion of this infinity of worlds with full, perfect, and exquisite life. The subtle scepticism of the human heart, ever ready to seize an occasion, again asserts itself. The attribute of power is magnified at the expense of the no less Godlike attribute which is satisfied with nothing less than perfection in detail. The world in its innate unbelief returns to the thought that even a love, a wisdom, a forethought which it mocks with the title of Divine, will fail to bestow upon each atom of this infinity, the care and tenderness which the race, in its infancy and ignorance, had fancied to be its own. And so God is pushed back and away from our human lives into a vague and dim abstraction, as the First Great Cause, and nothing more.

But “Wisdom,” now as of old, “is justified of her children.” Science is always its own antidote, and is ever ready with the solution of the difficulties which it has raised. A little waiting, and the tubes and lenses, the mechanical perfection and delicate adjustments which had created the doubt, resolved it. While the telescope was sweeping the fields of space,bringing within the ken of man new worlds, and systems of worlds in the universe of unknown vastness above us,—the microscope, in its humbler sphere, was revealing a no less wonderful universe of unknown beauty and perfection beneath us.

The line of telescopic discovery sweeping off into infinite space might well bring doubt and despair to the mind which contemplates that alone; but there is another line of discovery more beautiful, more wonderful still. As we look and tremble at the Divine power which holds the heavenly bodies in their orbits, we see it come circling round and beneath us, holding us safe within the magic bounds of that Divine love which has made man the central fact of creation.

This little instrument, then, has wrought a noble work for God and truth in the world. The microscope has, apart from its own peculiar work, a mission. Not only has it revealed to us many secrets which make life easier, which soften the pangs of disease and diminish the anguish of bereavement, but it has helped to silence the voice which was delivering its message of desolation to the world, in denying the Fatherhood of God. Not only does it show us the marvellous precision of inorganic nature, and the delicate adjustments of chemical, physical, and vital forces of organic, but it brings us into the very antechamber of that court where life holds its mysterious sway,—almost into the presence of the subtle vital force which baffles analysis, and laughs synthesis to scorn.

Let us begin at the very foundation of life, at its humblest manifestation, at the single stone, as it were, out of which all the magnificent architecture of organic nature is constructed. From the lowest form of life to the highest, from the most delicate sea-weed driven hither and thither by every passing ripple, up through the myriad forms of vegetable and animal life to man himself, there is no exception to the law which associates life, and all its functions, with the cell. In Nature's infinite variety there is nothing half so wonderful as the unity which underlies it all. The ideal type is still adhered to, throughout the numberless modifications of cell life. While there are cells of every size and shape, cells for the performance of every function of life, cells which go to make up every kind of tissue, yet, it is true, that every organic structure is in the main an aggregation of mere cells.

Vegetable cells, in the earlier stages of their development, generally approximate to the sphere in form. As they grow older, assume different offices in the economy of the plant, or are pressed upon by surrounding cells, the shape becomes changed. Each perfect vegetable cell is, in its earliest form, a sac of cellulose, filled with a mass of albuminous

jelly in which is embedded a roundish body,—the nucleus,-chemically like the surrounding jelly. The wall of cellulose (which is the substance afterward transformed into wood) constitutes the main feature by which vegetable are distinguished from animal cells.

Nothing could look more innocent than the contents of a vegetable or animal cell, and yet this harmless jelly is responsible for much bitter and rancorous warfare; it is the much-berated protoplasm,-“ the physical basis of life.” The name protoplasm, meaning first sorm, or first mould, has been given, because no form of life, vegetable or animal, fully developed or in embryo, has ever been found dissociated from it.

The protoplasm of a vegetable cell at first entirely fills the cellulose sac ; as the cell wall grows the jelly-like mass is seen to give way under the strain, and certain vacancies, called vacuoli, make their appearance, which become filled with cell sap. More and more of these liquid drops appear throughout the mass of protoplasm ; they generally coalesce at last, and form a central cavity, while the jelly is merely a lining membrane to the cellulose, or stretches itself across the cavity in the

« AnteriorContinuar »