The Invisible Kingdom, How Fungi and Microbes Reshape Our World

“ The Microbe is so very small
You cannot make him out at all,
But many sanguine people hope
To see him through a microscope. ”

“ Thus may our frog, besides its own marvels, afford us many “authentic tidings of invisible things,” and is itself a little colony of Life. Nature is economic as well as prodigal of space. She fills the illimitable heavens with planetary and starry grandeurs, and the tiny atoms moving over the crust of earth she makes the homes of the infinitely little. Far as the [Pg 70] mightiest telescope can reach, it detects worlds in clusters, like pebbles on the shore of Infinitude; deep as the microscope can penetrate, it detects Life within Life, generation within generation ”

“ The first acorn had wrapped up in it all the oak forests on the globe.
"Least of all seeds, greatest of all harvests," seems to be one of the great laws of nature. All life comes from microscopic beginnings. In nature there is nothing small. The microscope reveals as great a world below as the telescope above. All of nature's laws govern the smallest atoms, and a single drop of water is a miniature ocean. ”

“ The stony veil is rent, and they can look inimitable periods back, and see the curious animals which then moved up and down in the earth.
Once a glass bubble was a wonder for magnifying power. Now the lenses of the microscope bring an inverted universe to light. Men can look into a drop and discover an ocean crowded with millions of living creatures, monsters untypified in the visible world, playing about as in a great deep. ”

“ If we descend the scale of nature, reaching the extreme boundaries, the lowest forms, of the animal and vegetable kingdoms, we find members of these great divisions approximating so closely, that it becomes a matter of difficulty to draw any line of demarcation. The limits here are also hazy, because so far beyond the ken of unaided vision, and although the microscope has unveiled nature's secrets, disclosing a new world grand in the plenitude of its minutiæ, still its scientific eye is finite failing at times to decide which is the animal, and which the plant. ”

“ As to the former, the Attentive Reader of this Book will find, that there being hardly any thing so small, as by the help of Microscopes, to escape our enquiry, a new visible world is discovered by this means, and the Earth shews quite a new thing to us, so that in every little particle of its matter, we may now behold almost as great a variety of creatures, as we were able before to reckon up in the whole Universe it self. ”

“ Naturalists suppose another species, or order, of invisible animalcules; namely, such as escape the cognizance even of the best microscopes, and give many probable conjectures concerning them. Reason and analogy give some support to the existence of an infinite number of these imperceptible creatures. The naked eye, say some, takes in from the Elephant to the Mite; but there commences a new order, reserved only for the microscope, which comprehends all these from the Mite to those twenty-seven millions of times smaller ”

“ While astronomy, with its telescope, ranges beyond the known stars, and physiology, with its microscope, is subdividing infinite minutiae, we may expect that our historic centuries may be treated as inadequate counters in the history of the planet on which we are placed. We must expect new conceptions of the nature and relations of its denizens, as science acquires the materials for fresh generalizations; nor have we occasion for alarms if a highly advanced knowledge, like that of the eminent Naturalist before us, confronts us with an hypothesis as vast as it is novel. ”

“ The soil organisms are relatively immune to heat and cold, flood and drought. Even when a grain of soil has been made absolutely dry in the laboratory and then crushed to a very fine powder, they still remain. If it is placed in a sterile container filled with some fermentable material, a seething mass of microörganisms will appear in a few hours.
Some day this vast, unseen mass of life may be harnessed to the service of man. Only beginnings have been made to achieve this end. Some of the microscopic life forms are definitely helpful to plant life, while others undoubtedly are destructive. ”

“ As I gather it, the Solar sector of the Galaxy is alive with a violent evolution of fungus. We live in it, we breathe it, and we—eat it. They cringed in horror at what they found on the microscope slides, and this is the fourth pig I've killed. But I'm completely fungicided now, and I can handle 'em. But you see, Downing, you are alive with fungus spores looking for a place to live. They can't live on you, but what few that do escape the bactericidal action of the skin find it quite easy to go to work on an animal that has never been required to strive for life against fungi. ”

“ Now we have seen, when studying mushrooms, that the one difference between these green plants and the single-celled Fungi is that while the green cells make their own food, colourless cells can only take it in ready-made, and therefore prey upon all kinds of living matter. This is just what happens in the lichens; and botanists have discovered that these curious growths are really the result of a partnership between single-celled green plants and single-celled fungi. The grey part is a fungus; but when it is examined under the microscope we find it is not a fungus only ”

“ The roots of plants have no way to aggressively breakdown rock particles or organic matter, nor to sort out one nutrient from another. They uptake everything that is in solution, no more, no less while replacing water evaporated from their leaves. However, soil fungi are able to aggressively attack organic matter and even mineral rock particles and extract the nutrition they want. Fungi live in soil as long, complexly interconnected hair-like threads usually only one cell thick. ”

“ Although rather a common easily recognisable and aesthetically pleasing fungus growing in its characteristic clusters at the base of trees, it is a weak parasite entering the living tissue after invading decayed areas of the tree. This is the reason why when branches are broken off trees by wind, snow or storms, they should be carefully trimmed to remove ragged edges and the wound treated with a protective tar to stop the entry of rain, cold and fungus spores. Other more destructive fungi may enter a tree through such wounds ”

“ There are many poisonous fungi, but the greater number are harmless, though they are not intended for food. They simply clear away the decaying growths, and act as safety-valves to Nature by carrying away what is not required, to give it to the air again to be renewed into life. ”

“ In the penultimate zone the grass is dead, probably not caused by a direct parasitic attack but by the mycelial threads filling the air-spaces in the soil and so inhibiting water flow. This destruction of the delicate balance of water and air found in any soil induces drying out and gradual death of the plants whose roots permeate the soil. Behind the dead-zone is vegetation which shows increased vigour apparently due to plant-nutrients being released by the decaying mycelium and plant-material, whose death has been caused by the presence of the fungus. The innermost zone is not so stimulated. ”

“ He recommended growing "healing grass" for about five years following several years of vegetable gardening to erase all the exudate effects and restore the soil ecology to normal.
Mycorrhizal association is another beneficial relationship that should exist between soil organisms and many higher plants. This symbiotic relationship involves fungi and plant roots. Fungi can be pathogenic, consuming living plants. But most of them are harmless and eat only dead, decaying organic matter. ”

“ But in not a few cases they can render services in return, and, as we have seen in the case of the lichens, symbiosis may then occur. Fungi in general have the power of discovering and absorbing the least trace of water in the soil, and with it they absorb the salts necessary to the plant, and in this, apparently, consists the service which they are able to render even to large plants fixed deep in the earth, such as shrubs and trees. ”

“ Thus it is in the clearing of our American woodlands; where we burn down a forest of stately pines, a progeny of dwarf oaks start up in their place; and we never see the prostrate trunk of a tree mouldering into soil, but it gives birth to a whole tribe of fungi.
Let us not then, lament over the decay and oblivion into which ancient writers descend; they do but submit to the great law of Nature, which declares that all sublunary shapes of matter shall be limited in their duration, but which decrees, also, that their element shall never perish. ”

“ In every woodland, too, innumerable fungi are at work, raising from the lower soil rich substances, which, strewed on the surface by quick decay, will form food for plants higher than themselves; while they, by their variety and beauty, both of form and colour, might well form studies for any painter, and by the obscure laws of their reproduction, studies for any philosopher. Why, there is not a heap of dead leaves among which by picking it through carefully you might not find some twenty species of delicate and elegant land-shells ”

“ In woods and forests we can even more readily appreciate the good offices of fungi in accelerating the decay of fallen leaves and twigs which surround the base of the parent trees. In such places Nature is left absolutely to her own resources, and what man would accomplish in his carefully attended gardens and shrubberies must here be done without his aid. ”

“ In healthy, viable ecosystems, resources are constantly being recycled in a complexity of inter-related cycles. For instance nutrients in soil are taken up by plants, and the plants grow, die and decay to become part of the soil to nourish new plants. Within this process, the element nitrogen is taken up by plant roots as a vital nutrient and released again into the soil by the micro-organisms which are the agents of decay. These are two simple inter-related cycles in an ecosystem, but they are part of increasingly large resource-cycles, the largest of all being the Biosphere in which we live. ”

“ If the dead bodies of plants and animals of past ages simply accumulated on the surface of the ground without any forces to reduce them into simple compounds for dissipation, by their very bulk they would have long since completely covered the surface of the earth so as to afford no possible room for further growth of plants and animals. In a purely mechanical way, then, bacteria as decomposition agents are necessary to keep the surface of the earth fresh and unencumbered so that life can continue. ”

“ We cannot fathom the marvellous complexity of an organic being; but on the hypothesis here advanced this complexity is much increased. Each living creature must be looked at as a microcosm—a little universe, formed of a host of self-propagating organisms, inconceivably minute and as numerous as the stars in heaven. ”

“ It is interesting to contemplate an entangled bank, clothed with many plants of many kinds, with birds singing on the bushes, with various insects flitting about, and with worms crawling through the damp earth, and to reflect that these elaborately constructed forms, so different from each other, and dependent on each other in so complex a manner, have all been produced by laws acting around us. These laws, taken in the largest sense, being Growth with Reproduction; Inheritance which is almost implied by reproduction; ”

“ But he knows not what he desires when he wishes their extinction. For such is the balance of organic nature, that to strike out even one species, is like removing a link from a chain. Once broken, every other link is affected, and the whole chain lies useless upon the ground. Or, to speak without a figure, if you blot out certain species of animals or plants, you disturb the balance of the whole system of organic nature; nor can you tell where the disturbance thus introduced will end. It may lead to the excessive multiplication of species still more injurious than those you have destroyed. ”

“ If, in this net of interaction among species, even one of the nodes should exhibit unusual development or disappear, the balance of the ecosystem is disturbed; species that cannot stand the strain will perish, and the ecosystem then reorganizes itself to seek a new point of balance. This is what I mean by natural selection (the dispensation of Nature) . ”

“ But now we see those cleverly conceited, high-handed, and arrogant human beings invading the province of Nature, and trying their hand at biotechnology; in a short period of time they are attempting to change that which Nature has taken billions of years to make, or to create something new. The species adapt to their environments (air, water, sunlight, the Land, and the net of interactions among species) and survive by maintaining their balance through mutual assistance, but in order to do this it requires the total history of its own evolution since the time it appeared. ”

“ Again the engineer and the astronomer deal with the motions of real permanences in nature. Any theory of nature which for one moment loses sight of these great basic facts of experience is simply silly. But it is permissible to point out that the scientific expression of these facts has become entangled in a maze of doubtful metaphysics; and that, when we remove the metaphysics and start afresh on an unprejudiced survey of nature, a new light is thrown on many fundamental concepts which dominate science and guide the progress of research. ”

“ Modern scientists are boastful of their achievements in the field of discovery of Nature's laws and imagine they have learned almost all of Nature's secrets, while in truth they know but a few of her surface-laws the mainsprings of which are to be found deep down in the mental and spiritual strata of which they even dream not of—a realm which must ever remain closed to purely objective investigation. ”

“ When, however, we carefully examine the foundation of that assurance, we find reason to distrust its security; for it can be shown to be no less true of the scientific conception of Nature than it is of the artistic or the poetic, that it is a representation framed by the mind itself out of the materials supplied by the impressions which external objects make upon the senses, so that, to each man of science, Nature is what he individually believes her to be. ”