I.
It is said of Milton that in two short lines of poetry he made four mistakes in Natural History. He said of a whale:
“At his gills takes in,
And at his trunk lets out a sea.”
Now, in the first place, the whale has no gills; second, he takes in air instead of water; third, he throws out expired air; fourth, the water “spouted” is thrown up by the force of expiration, not out of the animal’s body, but water that may lie between the “blow-hole” and the surface of the sea.
I am not so sure but Milton made more than four mistakes in these lines. For whoever starts out on a wrong premise will follow a line of mistakes continually. Nevertheless, mistakes attentively observed may be profitable. We learn by mistakes. Unsuccessful experiments are mistakes of a kind—something wrong in the formula. The first aquarium I tried to start I made more mistakes than Milton made in his two lines. I made mistakes the second trial, and the third, and a dozen more times. And when I have succeeded in some instances, it was by accident, and to-day I can not tell why I sometimes failed, or why I sometimes succeeded. I have the consolation, however, of company in this respect. One of the most successful managers of aquaria says that he would give very much if he knew how to grow some of the higher marine algæ as one grows plants in a garden. Occasionally he has succeeded, but he confesses it was not by skill, but by chance.
I propose, therefore, that for a little while we consider the sea as an aquarium—a place adapted to the growth of animals and plants. Our subject is somewhat large, I must confess, but if we can see and understand how these things live and grow in the ocean we must be able to grow them in our parks, and possibly in our houses. For what Nature does on a grand scale may also be done in a small way; and principles that govern the successful growth of plants and animals in a bottle of sea water must be the same that govern the fauna and flora of the Pacific Ocean.
In order then to study and understand these things it will not be entirely necessary to make a trip to the equator, to the poles, or to travel around the world.
It has been a favorite theory with Henry D. Thoreau and John Burroughs, those genial and poetical lovers and observers of nature, that we need not rove all over the earth, as is the custom of many, to see this curiosity or that, or to observe nature in her secret recesses, but that we only have to sit down in the woods or by the sea-shore, and everything of interest will come round to us. The little town of Concord was a whole world in miniature to Thoreau. Everything worth finding could be found there. And so to John Burroughs, is the juniper forest of the Hudson, a show case, with the whole world inside. “Nature,” he says, “comes home to one most when he is at home; the stranger and traveler finds her a stranger and a traveler also.”
I think we may infer from this theory of our charming philosophers rather a poetical interpretation. They would urge a careful observation and study of phenomena in and near the places where we live, rather than gadding up and down the earth in search of novelties. If we familiarize ourselves with every day common objects and events of plants, animals, and other operations in nature, we shall then always be at home when nature calls, whether on one side or the other of the world.
I have heard of a good old lady who, when nearing the end of her earthly existence, said she did not mind the dying if she could only breathe. Now this goodly person had doubtless spent all the years of her life without observing the fact that every plant or animal however small or simple in structure must have, if nothing else, the organs for breathing, and when that function is suspended or destroyed, life ceases. The respiratory organs may be reduced to a single cell, wall, or membrane. The forms of these organs, however, are exceedingly variable, elaborate, and sometimes complicated.
In the sea, plants and animals have a compensatory relation to each other. The plant exhales oxygen and the animal exhales carbon. That is to say, the carbonic acid which is mixed mechanically with the water coming in contact with the cell, wall, or membrane, covering the plant, the atom of carbon is appropriated, freeing the two atoms of oxygen, which in turn are appropriated by the animal.
Not only is this process of breathing compensatory and reciprocative—an interchange of commodities—the plant giving two atoms of oxygen for one of carbon, and the animal bringing its single but equally valuable atom of carbon for two atoms of oxygen, but without this interchange, neither could plant or animal live, and our world of life would become as dead as the moon is supposed to be.
The process of breathing is so common that we seldom think about it, unless there is an interference in some way. Each one of us sitting quietly in this room would breathe about 1000 times in an hour, requiring over 100 gallons of air to sustain the proper supply of oxygen for the blood. During this time we have taken from the air a certain amount of oxygen and have returned to it an equal amount of something else, which we call carbon oxide, or carbonic acid gas. The oxygen has burned the effete material which is cast out of the blood in the process of breathing, and it is returned to the atmosphere as a kind of coal. The fundamental principle is the same in animals that breathe water as those that breathe air, only the apparatus is different. Animals that breathe water have a fine capillary network of blood-vessels spread out on gills, branchia or projections arranged so that the water shall pass rapidly over them, and thus the carbon is carried away and the oxygen taken into the circulation.
Animals that breathe air through lungs have little air cells, so very small that a human lung is said to contain 600 millions of them; and these lie in contact with the capillary circulation of the lung which receives the oxygen and gives out the carbon. Some air-breathers have no lungs, but merely spiracles or minute holes in the body through which the air enters, coming in contact with the circulation.
In all cases, whatever the form, size, or character of the animal the object is to bring the air in contact with the circulation that oxygen may be received in exchange for the burnt material—the carbon oxide—which, when once formed, is poisonous, and must be expelled from the animal.
Now if we look over the earth we shall find immense deposits of coal. Here in the United States we have nearly 200,000 square miles of coal deposits. In other countries there is a like proportion of these carbon deposits, such as petroleum, bitumen, and paraffine. Then there are great forests and other vegetable growth. These have stored up the carbon set free by the animal, and have kept the air comparatively free from carbonic acid gas, which but for the vegetables would in a little while have rendered our atmosphere unfit for animal use. What is true of the air in this respect is also true of the sea.
Thus it comes about that by the process of breathing, principally, we have the immense coal fields, the wide spread forests, and the herbage that covers almost the entire globe. For in the air and the water there exist the germs of animal and vegetable life so profusely, so universally, that the proper conditions of heat and light will develop contemporaneously, both the organic kingdoms. If we should take ten drops of water from the middle of the Pacific Ocean, near the surface, and add them to a small tube, say two ounces, of water that had been deprived of life by boiling, and kept sealed for a number of years, and place the tube in favorable conditions, we should in a few days see a little universe spring, as it were, into existence. There might not be a great variety of forms, but who can say that there might not be enough to populate or re-populate some world just entering into the conditions of such life as our earth contains, or some other world that had suffered a reverse, or cataclysm, by which all life was destroyed.
Mr. Lloyd, Superintendent of the Birmingham Aquarium, says he kept for eight years a bottle of sea water, well corked and covered with paper, and that when he opened it the water was perfectly clear, free from smell, and of the same appearance as when taken from the sea. But when exposed for eight days to light in a window an abundance of microscopic plants and animals began to grow, and soon covered the sides of the bottle, and darted about in the fluid.
Having occasion some ten months ago to use some sea-water, I brought to my house a demijohn full and placed it on the north side where the sun seldom shines, and where it is nearly always cool; although the temperature sometimes goes as high as 75° and 80° Fahrenheit in the afternoons. There was no particular effort to exclude light and air; the cork fitted loosely, and the wicker work was not unusually close. And yet, whenever I have examined this water it is clear and free from smell, and there are no plants or animals growing in it. But by exposure of a small quantity to the light and warmth of a window, these have rapidly developed. It is a fact, then, easily demonstrated in our own rooms and houses, that by excluding light from water and keeping it in a cool place we can arrest the growth of organisms. This is the case with springs. The microscope fails to discover germs in spring water until it has been exposed to the light for some time.
Acting on hints of this kind, Mr. Lloyd has constructed aquaria with two reservoirs—one in a dark, cool place, quite large—the other in a light and warm place, favorable to the growth of plants and animals. By means of pipes these two reservoirs are connected so that a circulation can be set up between the light and dark portions. A pump may be used to force the water from the dark reservoir into the other, using vulcanite or rubber of some kind for sea water, instead of such oxidizable metals as brass, tin, lead, etc. The most convenient temperature is about 60° Fahrenheit.
Thus, by exchanging the waters of these two reservoirs, as occasion requires, we shall be able to regulate an aquarium so as to keep many kinds of plants and animals in a healthy, growing condition.
The best aquaria are those where the water is never changed, but ever circulated in the manner I have indicated. Water that has once been made clear and good, and maintained plants and animals, is better than any water newly brought from the sea. It must be remembered that evaporation takes place from the surface of an aquarium more or less according to the heat and dryness of the air. At a temperature of 60° in an ordinary dry air, such as occurs some miles inland, the evaporation from a surface of water six inches square would be about three drops in twenty-four hours. Some very warm, dry days it would be two or three times that much. This waste must be made up by adding occasionally some distilled water.
An aquarium must be kept free of decaying matter. If once formed the sooner it is got rid of the better, for it will poison all creatures that come within its influence. The larger the dark reservoir the better. It can not be too large, but should be not less than four or five times larger than the reservoir in which the plants and animals are kept. Any dead matter then will quickly be burned at a low temperature—for oxygenation by means of the dark reservoir means no more nor less than the burning up of the effete and decaying particles thrown off by plants and animals.
It might be profitable for me to tell now how I didn’t succeed with the first aquarium I undertook.
It was a fine, large structure, capable of holding some twenty gallons. The sea water was procured, and at low tide a friend went with me to help carry an assortment of plants and animals. We had read a good deal about the compensatory properties of these two kingdoms; how the plants exhale oxygen and inhale carbon, and how the animals inhale oxygen and exhale carbon, and thus preserve the equilibrium and the purity of the water. Well, we had good luck in searching tide-pools, and the turning over of rocks; and we returned loaded with snails, crabs, sea-anemones, sea-urchins, clams, abelones, date fish, real fish, sea worms (with beautiful red branchia), and sea weeds, an extensive variety of red, green and brown, only one or two of which would grow, as I have since learned, even in the most successful aquarium yet known. There are many other things that I have forgotten. We had rock-work and sand, and pebbles of beautiful colors, and a great many iridea, a rainbow-colored sea weed. We intended to imitate one of the beautiful tide-pools we had seen, and astonish our friends with a little bit of the sea, snatched up and transported to our quiet room, away from the fog and wind and chill of the ocean shore. We would willingly have brought the tide and some waves, if they could have been dwarfed to the dimensions of our tank. With these and a few other things we might have succeeded, and kept our aquarium as long as Robert Warrington kept his in London, with unchanged water, during a period of eighteen years.
But in eighteen hours our animals were all dead or dying; and although the plants were in proportion—that is, we had an equilibrium—they were almost equally in as bad a condition as the animals. First the water began to turn cloudy. We looked at our books for light, but they were equally obscure. Then we perceived a smell, somewhat like canned oysters, and this smell grew till it permeated the whole house. We suspected something wrong, so we emptied the aquarium, filtered the water, threw away the decaying matter, and put the things in again. But the “muddy vesture of decay” had covered the stones and entered the crevices, and in a few hours more we had to cast the contents away. The fact is, as I have learned since, we had a large number of bruised, broken and bleeding organisms from the handling in transfer, that the whole ocean’s waters could not save or heal, much less the little tank of twenty gallons. There were no waves to carry away the dead matter, no oxygen in the water to burn it, so it had to be breathed over and over again until the blood was poisoned and the animal died, because it could breathe such water no longer. And the plants began to fade and decay because their blood was also poisoned.
Now let us turn and consider for a moment Nature’s aquarium—the sea. It covers two-thirds of the earth’s surface, and it has been explored to the depth of eight miles at places, without finding bottom. The average depth, however, is about 2½ miles. All this immense mass of salt water is inhabited with a fauna and flora in a state of nature. That is, the hand of man has done nothing in the way of taming or cultivating them. They are absolutely wild, whilst a large part of the earth is subject to man’s dominion, and he was commanded to subdue it. The herbs and the trees of the field “shall be for meat,” and his “dominion over the fish of the sea, and over the fowl of the air,” pronounced at creation, is, as yet, but partially accomplished. The sea and the air remain as mysteries unsolved, and as powers unconquered. The cyclone and the tidal wave are evidences of the untamableness of these elements. “He bindeth up the waters in thick clouds, and the cloud is not rent under them,” was the language of some thirty-five centuries ago, and it is equally as true and expressive to-day.
Although the sea is inhabited at all depths, according to the best knowledge we have at present much the largest part lies beyond daylight. Light only penetrates a few fathoms—all below is darkness. This is the great, deep, cool reservoir from which the upper strata is constantly renewed by a circulation about which we, as yet, know but little. How is this circulation kept up? Who has charge of “the doors of the sea?” Who has “entered into the springs of the sea,” or “walked in search of the depth?” We have some knowledge in regard to these questions. The investigations of such men as Edward Forbes, Sir William Thompson, Dr. Wm. B. Carpenter, Lieut. M. F. Maury, Darwin, Kane, and a host of other scientific explorers equally as wise and industrious, have solved many mysteries in regard to the great ocean of salt water, and that lighter ocean of air that surrounds the earth.
Many years ago Maury wrote some striking and impressive sentences in his “Physical Geography of Sea,” such as the following:
“Our planet is invested with two great oceans; one visible, the other invisible; one underfoot, the other overhead; one entirely envelops it, the other covers about two-thirds of its surface. All the water of the one weighs about four hundred times as much as all the air of the other.”
Then again in reference to the Gulf Stream he says: “There is a river in the ocean; in the severest droughts it never fails; in the mightiest floods it never overflows; its banks and its bottom are of cold water, while its current is of warm. The Gulf of Mexico is its fountain, and its mouth is in the Arctic Seas. Its current is more rapid than the Mississippi or the Amazon, and its volume more than a thousand times greater. Its waters are of an indigo blue. They are so distinctly marked that their line of junction with the common sea water may be traced by the eye. Often one-half of the vessel may be perceived floating in Gulf Stream water, while the other half is in common water of the sea, so sharp is the line and such the want of affinity between those waters, and such, too, the reluctance, so to speak, on the part of those of the Gulf Stream to mingle with the littoral waters of the sea.”
We have all read and doubtless thought a great deal about this wonderful stream; how England and the shores of the continent are warmed by this water. But there are other streams equally important, if not so distinctly marked. Every ocean and sea has its current or currents. As the waters are warmed by the rays of the sun, they expand and flow away. But these streams are not very deep, and the Gulf Stream is shallow compared with the dark, cold current that moves below it, but in an opposite direction.
[To be continued.]
