This last substance is, again, one of those trifles without which existence would be impossible. In the stomach there is a trifling quantity of it, manufactured as required, which kills most of the microbes, we swallow in food, prevents fermentation, and helps digestion.
There are ever so many other inorganic compounds. Besides these, all civilised bodies contain a regular laboratory of adulterants, such as boric acid and salicylic acid taken with milk, butter, and meat, and kept some time in the body; iron, copper, antimony, arsenic, and many other things taken in tea, beer, bottled vegetables, and the like.
SUGAR MAKING IS CARRIED ON IN THE BODY—THOUGH THERE IS NEVER MORE THAN A BOWLFUL OF IT.
From these comparatively simple bodies we go up to what are called the organic compounds. There is a whole host of organic acids. Of course these are present in very small quantities, or else they would dissolve us like so much sugar.
The salts, the acids, and the elements are still more complexly associated. One mixture of them forms the proteid or albuminous substance which scarcely differs from white of egg. It is this alone, in fact, that lives. It is the chief solid part of muscle, heart, lung, brain, nerve, blood, and exists in every fluid and solid of the body (including sweat and saliva), except bile and one other substance. What distinguishes proteid from everything else is that it contains the lifeless gas nitrogen.
Perhaps the nearest approach one could give to a definition of life is that it consists of the separation of the carbon and nitrogen of proteid substance.
The proteid is taken into the body ready-made, in milk, meat, eggs, fish, and to a less extent in vegetables.
"Hamlet" and "King Lear," the "Iliad" and "Paradise Lost," every speech and sermon one hears, and every book one reads, is really for the most part this dissociation of carbon from nitrogen in another man's brain, made evident to our eyes or ears. And this dissociation is nothing more than if you took some white of egg and mixed with it a quantity of oxygen so as to form urea, carbonic acid, and water.
