Picture - Cosmic Polymath

GROMIA 343
The barramunda is credited with the power of going on land, or at least mud-flats. As the fish is heavy, and
its pectoral and ventral fins or limbs weak, it is in no way adapted to land transit. It is, however, quite equal
to making considerable progress on a marshy soft bottom. While the fish is beheved to have the power of leaving
the water for short intervals and of breathing by its lung alone, it is more than doubtful if it can survive in a healthy
condition for any length of time out of water. The perfect state of its gills favours this beUef, -and its one lung
would be quite inadequate for protracted air-breathing purposes. What in all probability happens is, that the lung
is an auxihary structure, and that the fish breathes habitually by its gills, and employs its lung as an adjunct for
taking in great gulps of air when the animal, partly asphyxiated by the gases of the foul water, rises to the surface,
which it is constantly in the habit of doing when the conditions of breathing are rendered difficult.
The rising to the surface for the purpose of breathing air also obtains in the sea mammals, where no gills are
present, and oxygenation of the blood is effected wholly by the employment of lungs.
One of the most remarkable animals as far as breathing is concerned is the axolotl (Siredon jrisciformis). It
is provided with six feathery-looking gills, which are arranged on the outside of the body separately, three on each
side of the head. The axolotl is a water-breather, and confines its operations exclusively to this medium. Some
years since Professor Haeckel ^ asserted that this quaint creature can convert itself from a water-breather into an
air-breather, and he instances some experiments to this effect which he asserts were made at the Zoological Gardens,
Paris, where a large number of axolotls are kept and bred. This statement requires to be taken with the extreme
of caution, and is as follows : " The water-salamanders, or tritons, which have been artificially made to retain their
original gills, are extremely interesting in this respect. The tritons are amphibious animals, nearly akin to frogs,
and possess, like the latter, in their youth external organs of respiration— gills—with which they, while hving in
water, breathe the air dissolved in the water. At a later date a metamorphosis takes place in tritons, as in frogs.
They leave the water, lose their gills, and accustom themselves to breathe with their lungs. But if they are prevented
from doing this by being kept shut up in a tank, they do not lose their gills. The gills remain, and the water-
salamander continues through Ufe in that low stage of development, beyond which its lower relations, the gilled
salamanders, or Sozobranchiata,^ never pass." It will be observed that the experiments referred to in this quota-
tion are wholly artificial, and of httle or no value as far as exact science is concerned. He continues, " Great interest
was caused a short time ago, among zoologists, by the axolotl (Siredon pisciformis), a gilled salamander from Mexico,
nearly related to the triton ; it had already been known for a long time, and been bred on a large scale in the
Zoological Gardens in Paris. This animal possessess external gills, like the young salamander, but retains them all its
life, like all other Perermibranchiata. This gilled salamander generally remains in the water, with its aquatic organs
of respiration, and also propagates itself there. Bvt in the Paris garden, unexpectedly from among hundreds of these
animals, a small number crept out of the water on to the dry land, lost their gills, and changed themselves into gill-less
salamanders, which cannot be distinguished from a North American genus of tritons (Amblystoma), and breathe only
through limgs." (The itahcs are mine.)
I cannot help feeUng that some important error has been committed in this connection. Of course, Haeckel
admits the whoUy artificial nature of the experiments, but he seems to have mixed up conditions which are essen-
tially separate and distinct, and which are even contradictory in their nature. They are altogether at variance with
similar experiments made by myself with young frogs, where the artificial and objectionable features were eliminated.
I found that a period arrives in the development of the frog when nature must have fair play and free play. This
occurs when the lungs are fully developed and the gills have become useless as water-breathing organs. If at this
stage no provision be made for the young frogs leaving the water, resting, and breathing air, they are drowned. It
is necessary under the circumstances to erect in the aquarium small, slanting, elevated platforms of stone, brick, earth,
or some such material, to permit the young frogs to leave the water and to breathe air at discretion and imder favour-
able conditions. It would defeat the object in view to confine the young frogs exclusively to the water when their
arrangements for living in that element have disappeared. We might as well expect the eye to see and the ear to
hear when the organs of sight and hearing have, from some cause or other, been destroyed.
It is not permissible to substitute an artificial for a natural process in a growing organism, especially if the
artificial arrangements are opposed to nature and bar progress. If an experiment gives an unnatural bias to or
stints development, it at once becomes misleading, and Uttle or no importance can be attached to it.
The foregoing affords no proof that the important respiratory processes can be indefinitely modified, and that
a water-breathing animal can, within a comparatively short period, be converted into an air-breathing one. Such
a possibiUty would upset the whole scheme of nature, and lead to the dangerous conclusion that all parts of plants
and animals are interchangeable, and that the one is directly or indirectly manufactured out of the other.
In this connection it may be useful to state that the sea mammals, such as the whales, porpoises, dugongs,
1 "The History of Creation," vol. i. p. 259 ei seq.
" Ordinarily known as Perennibranchiata.