Page:Popular Science Monthly Volume 43.djvu/552

536 The living cell is made up of organic and inorganic constituents. It contains carbon, hydrogen, oxygen, nitrogen, sulphur, phosphorus, chlorine, sodium, potassium, calcium, magnesium, fluorine, silicon, and iron. All these are necessary to life. Abstraction of one of these elements means death to the organization.

We have traced life down to the cell. The lowest forms of life, both animal and vegetable, are single cells, and from these single cells, according to the theory of evolution, all life has been produced. But how about the origin of the first cell? We do not believe in spontaneous generation—that is to say, no case of the spontaneous generation of life from its elements has ever been recorded by man. But we may reason thus: All substances, even the simplest, require certain conditions for their production. The conditions required to produce a living cell must of necessity be extremely complicated. We do not know of such conditions, but for the sake of argument we may imagine that at some former period of the world's history conditions may have existed favorable to the production of the first life.

When we seek to define life we uncover a difficult problem. But who can define the steam engine? There is no satisfactory definition for either. We can merely say that life is the result of the activity of the cells.

It follows from this that it is useless to seek for a seat of life. The seat of life has been placed in the blood, but this is the nourishing fluid; in the heart, which is merely the pump for the blood; in the medulla oblongata, but this contains the nervous center for breathing. There is no such thing as a seat of life. Life is the result of the activity of all the organs of the body.

To every living thing there at last must come an end, and in this fact of death the advocates of a "vital force" saw the necessity for their theory. But this is explicable in a material manner. In life, as in death, decompositions are continually going on. These decompositions are in kind not different, only during life the products of decomposition are removed, and at death these products remain in the body and poison the individual cells—that is, so alter them that their conditions no longer fulfill the requirements of life.

The uneducated Indian when first shown a watch thought that it was alive; we, on the contrary, have come to regard the living organization as a machine. Upon this basis alone can physiology endure as a science, and physiology is, as the reader knows, nothing Init the study of the phenomena of life.

I have endeavored, up to this point, to give an exposition of the material view of life as complete as the most exacting materialist could desire. Many men reach this point and refuse to see further; they make materialism their creed, and cast religion to