A Series of Lessons in Gnani Yoga: The Yoga of Wisdom

by William Walker Atkinson

The flexibility of the vertebra creates a wonderful strength of structure, combined with an ease of movement peculiar to the vertebrates, and which renders them the natural forms of life capable of rapid development and evolution. By means of this strength, and ease, these forms are enabled to move rapidly in pursuit of their prey, and away from their pursuers, and also to resist outside pressure or attack. They are protected in a way similar to the invertebrates having shells, and yet have the additional advantage of easy movement. Differing in shape and appearance as do the numerous members of the sub-family of vertebrates, still their structure is easily seen to spring from a single form—all are modifications of some common pattern, the differences arising from the necessities of the life of the animal, as manifested through the desire and necessities of the species.

Science shows the direct relationship between the Vertebrates, and the Invertebrates by means of several connecting-links, the most noticeable of which is the Lancelot, a creature resembling the fish-form, and yet also closely resembling the lower (invertebrate) forms of life. This creature has no head, and but one eye. It is semi-transparent, and possesses cilia for forcing in the water containing its food. It has something like gills, and a gullet like the lower forms. It has no heart, the blood being circulated by means of contracting vessels or parts. Strictly speaking, it has no back-bone, or vertebra, but still Science has been compelled to class it among the vertebrates because is has a gristly cartilage where the back-bone is found in the higher forms. This gristle may be called an "elementary spine." It has a nervous system consisting of a single cord which spreads into a broadened end near the creature's mouth, and which may therefore be regarded as "something like a brain." This creature is really a developed form of Invertebrate, shaped like a Vertebrate, and showing signs of a rudimentary spine and nervous system of the latter. It is a "connecting-link."

The lowest forms of the true Vertebrates are the great families of Fishes. These Fish families include fishes of high and low degree, some of the higher forms being as different from the lowest as they (the highest) are different from the Reptile family. It is not necessary to go into detail regarding the nature of the fish families, for every student is more or less familiar with them.

Some peculiar forms of fish show a shading into the Reptile family, in fact they seem to belong nearly as much to the latter as to their own general family. Some species of fish known as the Dipnoi or "double-breathers," have a remarkable dual system of breathing. That is, they have gills for breathing while in the water, and also have a primitive or elementary "lung" in the shape of an air-bladder, or "sound," which they use for breathing on land. The Mud-fish of South America, and also other forms in Australia and other places, have a modification of fins which are practically "limbs," which they actually use for traveling on land from pond to pond. Some of these fish have been known to travel enormous distances in search of new pools of water, or new streams, having been driven from their original homes by droughts, or perhaps by instincts similar to the migrating instinct of birds. Eels are fish (although many commonly forget this fact) and many of their species are able to leave the water and travel on land from pond to pond, their breathing being performed by a peculiar modification of the gills. The climbing perch of India are able to live out of water, and have modified gills for breathing purposes, and modified fins for climbing and walking. So you see that without leaving the fish family proper, we have examples of land living creatures which are akin to "connecting links."

But there are real "connecting-links"' between the Fish and the Reptiles. Passing over the many queer forms which serve as links between the two families, we have but to consider our common frog's history for a striking example. The Tadpole has gills, has no limbs, uses its tail like a fish's fin, eats plants, etc. Passing through several interesting stages the Tadpole reaches a stage in which it is a frog with a tail—then it sheds its tail and is a full fledged Frog, with four legs; web-feet; no tail; and feeding on animals. The Frog is amphibious, that is, able to live on land or in water—and yet it is compelled to come to the surface of the water for air to supply its lungs. Some of the amphibious animals possess both lungs and gills, even when matured; but the higher vertebrates living in the water breathe through lungs which are evolved from the air-bladder of fishes, which in turn have been evolved from the primitive gullet of the lower forms. There are fishes known which are warm-blooded. Students will kindly remember that the Whale is not a fish, but an aquatic animal—a mammal, in fact, bringing forth its young alive, and suckling it from its breasts.

So we readily see that it is but a step, and a short step at that, between the land-traveling and climbing fishes and the lower forms of Reptiles. The Frog shows us the process of evolution between the two families, its life history reproducing the gradual evolution which may have required ages to perfect in the case of the species. You will remember that the embryo stages of all creatures reproduce the various stages of evolution through which the species has passed—this is true in Man as well as in the Frog.

We need not tarry long in considering the Reptile family of living forms. In its varieties of serpents, lizards, crocodiles, turtles, etc., we have studied and observed its forms. We see the limbless snakes; the lizards with active limbs; the huge, clumsy, slow crocodiles and alligators—the armor-bearing turtles and tortoises—all belonging to the one great family of Reptiles, and nearly all of them being degenerate descendants of the mighty Reptile forms of the geological Age of Reptiles, in which flourished the mighty forms of the giant reptiles—the monsters of land and water. Amidst the dense vegetation of that pre-historic age, surrounded by the most favorable conditions, these mighty creatures flourished and lived, their fossilized skeleton forms evidencing to us how far their descendants have fallen, owing to less favorable conditions, and the development of other life-forms more in harmony with their changed environment.

Next comes the great family of Birds. The Birds ascended from the Reptiles. This is the Eastern Teaching, and this is the teaching of Western Science It was formerly taught in the text-books that the line of ascent was along the family of winged reptiles which existed in the Age of Reptiles, in the early days of the Earth. But the later writers on the subject, in the Western world, have contradicted this. It is now taught that these ancient winged-reptiles were featherless, and more closely resembled the Bat family than birds. (You will remember that a Bat is neither a reptile nor a bird—it is a mammal, bringing forth its young alive, and suckling them at its breast. The Bat is more like a mouse, and its wings are simply membrane stretched between its fingers, its feet, and its tail.)

The line of ascent from Reptile to Bird was along the forms of the Reptiles that walked on land. There are close anatomical and physiological relations and correspondences between the two families (Reptiles and Birds) which we need not refer to here. And, of course, many modifications have occurred since the "branching-out." The scales of the reptiles, and the feathers of the birds, are known to be but modifications of the original outer skin, as are also the hair, claws, hoofs, nails, etc., of all animals. Even teeth arose in this way, strange as it may now seem—they are all secreted from the skin. What a wonderful field for thought—this gradual evolution from the filmy outer covering of the lowest living forms to the beautiful feathers, beaks, and claws of the bird!

The evolving of wings meant much to the ascending forms of life. The Reptiles were compelled to live in a narrow circle of territory, while the Birds were able to travel over the earth in wide flights. And travel always develops the faculties of observation, memory, etc., and cultivates the senses of seeing, hearing, etc. And the creature is compelled to exercise its evolving "thinking" faculties to a greater extent. And so the Birds were compelled by necessity of their travels to develop a greater degree of thinking organism. The result is that among birds we find many instances of intelligent thought, which cannot be dismissed as "mere instinct." Naturalists place the Crow at the head of the family of Birds, in point of intelligence, and those who have watched these creatures and studied the mental processes, will agree that this is a just decision. It has been proven that Crows are capable of counting up to several figures, and in other ways they display a wonderful degree of almost human sagacity.