Post 00273
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Biological science has hunted the secret of vitality like a detective; and it has done some famous work; but it has not yet unraveled the mystery. It knows well the part played by carbon, oxygen, and hydrogen in organic chemistry, that without water and carbon dioxide there could be no life; it knows the part played by light, air, heat, gravity, osmosis, chemical affinity, and all the hundreds or thousands of organic compounds; it knows the part played by what are called the enzymes, or ferments, in all living bodies, but it does not know the secret of these ferments; it knows the part played by colloids, or jelly-like compounds, that there is no living body without colloids, though there are colloid bodies that are not living; it knows the part played by oxidation, that without it a living body ceases to function, though everywhere all about us is oxidation without life; it knows the part played by chlorophyll in the vegetable kingdom, and yet how chlorophyll works such magic upon the sun’s rays, using the solar energy to fix the carbon of carbonic acid in the air, and thereby storing this energy as it is stored in wood and coal and in much of the food we consume, is a mystery. Chemistry cannot repeat the process in its laboratories. The fungi do not possess this wonderful chlorophyllian power, and hence cannot use the sunbeam to snatch their carbon from the air; they must get it from decomposed vegetable matter; they feed, as the animals do, upon elements that have gone through the cycle of vegetable life. The secret of vegetable life, then, is in the green substance of the leaf where science is powerless to unlock it. Conjure with the elements as it may, it cannot produce the least speck of living matter. It can by synthesis produce many of the organic compounds, but only from matter that has already been through the organic cycle. It has lately produced rubber, but from other products of vegetable life.
As soon as the four principal elements, carbon, oxygen, hydrogen, and nitrogen, that make up the living body, have entered the world of living matter, their activities and possible combinations enormously increase; they enter into new relations with one another and form compounds of great variety and complexity, characterized by the instability which life requires. The organic compounds are vastly more sensitive to light and heat and air than are the same elements in the inorganic world. What has happened to them? Chemistry cannot tell us. Oxidation, which is only slow combustion, is the main source of energy in the body, as it is in the steam-engine. The storing of the solar energy, which occurs only in the vegetable, is by a process of reduction, that is, the separation of the carbon and oxygen in carbonic acid and water. The chemical reactions which liberate energy in the body are slow; in dead matter they are rapid and violent, or explosive and destructive. It is the chemistry in the leaf of the plant that diverts or draws the solar energy into the stream of life, and how it does it is a mystery.
The scientific explanations of life phenomena are all after the fact; they do not account for the fact; they start with the ready-made organism and then reduce its activities and processes to their physical equivalents. Vitality is given, and then the vital processes are fitted into mechanical and chemical concepts, or into moulds derived from inert matter–not a difficult thing to do, but no more an explanation of the mystery of vitality than a painting or a marble bust of Tyndall would be an explanation of that great scientist.