incipient development of deafness in children. Where the capacity of
hearing is quickly lowered from the normal to fifty per cent, it is so
striking that the patient is much distressed and even confused. But
when this change takes place insidiously from day to day, it is
frequently not observed by either the patient or those around him
until it has greatly advanced. Children thus affected hear only with
difficulty and by straining certain small muscles of the ear, which
soon become fatigued, and the child becomes listless and inattentive.
I have seen numerous cases in which children have been severely
punished for inattention, when this was due to defective hearing.
Watchfulness and early attention in these cases will frequently
prevent the more serious forms of deafness.
THE PHYSICAL GEOGRAPHY OF THE WEST INDIES.
BY F. L. OSWALD.
I.--THE FAUNA OF THE ANTILLES: MAMMALS.
The study of the geographical distribution of plants and animals has
revealed facts almost as enigmatical as the origin of life itself.
Water barriers, as broad as that of the Atlantic, have not prevented
the spontaneous spread of some species, while others limit their
habitat to narrowly circumscribed though not geographically isolated
regions.
Tapirs are found both in the Amazon Valley and on the Malay Peninsula;
the brook trout of southern New Zealand are identical with those of
the Austrian Alps. Oaks and _Ericacea_ (heather plants) cover northern
Europe from the mouth of the Seine to the sources of the Ural; then
suddenly cease, and are not found anywhere in the vast Siberian
territories, with a north-to-south range rivaling that of all British
North America.
But still more remarkable is the zoölogical contrast of such
close-neighborhood countries as Africa and Madagascar, or Central
America and the West Indian archipelago. The Madagascar virgin woods
harbor no lions, leopards, hyenas, or baboons, but boast not less than
thirty-five species of mammals unknown to the African continent, and
twenty-six found nowhere else in the world.
Of a dozen different kinds of deer, abundant in North America as well
as in Asia and Europe, not a single species has found its way to the
West Indies. The fine mountain meadows of Hayti have originated no
antelopes, no wild sheep or wild goats.
In the Cuban sierras, towering to a height of 8,300 feet, there are no
hill foxes. There are caverns--subterranean labyrinths with countless
ramifications, some of them--but no cave bears or badgers, no marmots
or weasels even, nor one of the numerous weasel-like creatures
clambering about the rock clefts of Mexico. The magnificent coast
forests of the Antilles produce wild-growing nuts enough to freight a
thousand schooners every year, but--almost incredible to say--the
explorers of sixteen generations have failed to discover a single
species of squirrels.
The Old-World tribes of our tree-climbing relatives are so totally
different from those of the American tropics that Humboldt's traveling
companion, Bonplant, renounced the theory of a unitary center of
creation (or evolution), and maintained that South America must have
made a separate though unsuccessful attempt to rise from lemurs to
manlike apes and men. Of such as they are, Brazil alone has
forty-eight species of monkeys, and Venezuela at least thirty. How
shall we account for the fact that not one of the large West Indian
islands betrays a vestige of an effort in the same direction?
More monkey-inviting forests than those of southern Hayti can not be
found in the tropics, but not even a marmoset or squirrel-monkey
accepted the invitation. In an infinite series of centuries not one
pair of quadrumana availed itself of the chance to cross a sea gap,
though at several points the mainland approaches western Cuba within
less than two hundred miles--about half the distance that separates
southern Asia from Borneo, where fourhanders of all sizes and colors
compete for the products of the wilderness, and, according to Sir
Philip Maitland, the "native women avoid the coast jungles for fear of
meeting Mr. Darwin's grandfather."
The first Spanish explorers of the Antilles were, in fact, so amazed
at the apparently complete absence of quadrupeds that their only
explanation was a conjecture that the beasts of the forest must have
been exterminated by order of some native potentate, perhaps the great
Kubla Khan, whose possessions they supposed to extend _eastward_ from
Lake Aral to the Atlantic. The chronicle of Diego Columbus says
positively that San Domingo and San Juan Bautista (Porto Rico) were
void of mammals, but afterward modifies that statement by mentioning a
species of rodent, the _hutia_, or bush rat, that annoyed the
colonists of Fort Isabel, and caused them to make an appropriation for
importing a cargo of cats.
Bush rats and moles were, up to the end of the sixteenth century, the
only known indigenous quadrupeds of the entire West Indian
archipelago, for the "Carib dogs," which Valverde saw in Jamaica, were
believed to have been brought from the mainland by a horde of
man-hunting savages.
But natural history has kept step with the advance of other sciences,
and the list of undoubtedly aboriginal mammals on the four main
islands of the Antilles is now known to comprise more than twenty
species. That at least fifteen of them escaped the attention of the
Spanish creoles is as strange as the fact that the Castilian cattle
barons of Upper California did not suspect the existence of precious
metals, though nearly the whole bonanza region of the San Joaquin
Valley had been settled before the beginning of the seventeenth
century. But the conquerors of the Philippines even overlooked a
variety of elephants that roams the coast jungles of Mindanao.
Eight species of those West Indian _incognito_ mammals, it is true,
are creatures of a kind which the Spanish zoölogists of Valverde's
time would probably have classed with birds--bats, namely, including
the curious _Vespertilio molossus_, or mastiff bat, and several
varieties of the owl-faced _Chilonycteris_, that takes wing in the
gloom preceding a thunderstorm, as well as in the morning and evening
twilight, and flits up and down the coast rivers with screams that
can be heard as plainly as the screech of a paroquet. The _Vespertilio
scandens_ of eastern San Domingo has a peculiar habit of flitting from
tree to tree, and clambering about in quest of insects, almost with
the agility of a flying squirrel. There are times when the moonlit
woods near Cape Rafael seem to be all alive with the restless little
creatures; that keep up a clicking chirp, and every now and then
gather in swarms to contest a tempting find, or to settle some probate
court litigation. San Domingo also harbors one species of those
prototypes of the harpies, the fruit-eating bats. It passes the
daylight hours in hollow trees, but becomes nervous toward sunset and
apt to betray its hiding place by an impatient twitter--probably a
collocution of angry comments on the length of time between meals. The
moment the twilight deepens into gloom the chatterers flop out to fall
on the next mango orchard and eat away like mortgage brokers. They do
not get fat--champion gluttons rarely do--but attain a weight of six
ounces, and the Haytian darkey would get even with them after a manner
of their own if their prerogatives were not protected by the intensity
of their musky odor. The above-mentioned _hutia_ rat appears to have
immigrated from some part of the world where the shortness of the
summer justified the accumulation of large reserve stores of food, and
under the influence of a hereditary hoarding instinct it now passes
its existence constructing and filling a series of subterranean
granaries. Besides, the females build nurseries, and all these burrows
are connected by tunnels that enable their constructors to pass the
rainy season under shelter. They gather nuts, _belotas_ (a sort of
sweet acorns), and all kinds of cereals, and with their _penchant_ for
appropriating roundish wooden objects on general principles would
probably give a Connecticut nutmeg peddler the benefit of the doubt.
They also pilfer raisins, and a colony of such tithe collectors is a
formidable nuisance, for the _hutia_ is a giant of its tribe, and
attains a length of sixteen inches, exclusive of the tail. It is found
in Cuba, Hayti, Jamaica, Porto Rico, Antigua, Trinidad, the Isle of
Pines, Martinique, and two or three of the southern Bahama Islands,
and there may have been a time when it had the archipelago all to
itself. The Lucayans had a tradition that their ancestors found it on
their arrival from the mainland, and in some coast regions of eastern
Cuba it may still be seen basking in the sunlight--
"Sole sitting on the shore of old romance,"
and wondering if there are any larger mammals on this planet.
Its next West Indian congener is the Jamaica rice rat, and there are
at least ten species of mice, all clearly distinct from any Old-World
rodent, though it is barely possible that some of them may have stolen
a ride on Spanish trading vessels from Central America.
Water-moles burrow in the banks of several Cuban rivers, and two
genera of aquatic mammals have solved the problem of survival: the
bayou porpoise and the manatee, both known to the creoles of the early
colonial era, and vaguely even to the first discoverers, since
Columbus himself alludes to a "sort of mermaids (_sirenas_) that half
rose from the water and scanned the boat's crew with curious eyes."
Naturally the manatee is, indeed, by no means a timid creature, but
bitter experience has changed its habits since the time when the
down-town sportsmen of Santiago used to start in sailboats for the
outer estuary and return before night with a week's supply of manatee
meat. The best remaining hunting grounds are the reed shallows of
Samana Bay (San Domingo) and the deltas of the Hayti swamp rivers. Old
specimens are generally as wary as the Prybilof fur seal that dive out
of sight at the first glimpse of a sail; still, their slit-eyed
youngsters are taken alive often enough, to be kept as public pets in
many town ponds, where they learn to come to a whistle and waddle
ashore for a handful of cabbage leaves.
Fish otters have been caught in the lagoons of Puerto Principe
(central Cuba) and near Cape Tiburon, on the south coast of San
Domingo, the traveler Gerstaecker saw a kind of "bushy-tailed
dormouse, too small to be called a squirrel."
But the last four hundred years have enlarged the list of indigenous
mammals in more than one sense, and the Chevalier de Saint-Méry should
not have been criticised for describing the bush dog of Hayti as a
"_canis Hispaniolanus_." Imported dogs enacted a declaration of
independence several centuries before the revolt of the Haytian
slaves, and their descendants have become as thoroughly West Indian as
the Franks have become French. A continued process of elimination has
made the survivors climate-proof and self-supporting, and above all
they have ceased to vary; Nature has accepted their modified type as
wholly adapted to the exigencies of their present habitat. And if it
is true that all runaway animals revert in some degree to the
characteristics of their primeval relatives, the ancestor of the
domestic dog would appear to have been a bush-tailed, brindle-skinned,
and black-muzzled brute, intermittently gregarious, and combining the
burrowing propensity of the fox with the co-operative hunting
_penchant_ of the wolf.
Fourteen years of bushwhacker warfare have almost wholly exterminated
the half-wild cattle of the Cuban sierras, but the bush dog has come
to stay. The yelping of its whelps can be heard in thousands of jungle
woods and mountain ravines, both of Cuba and Hayti, and no variety of
thoroughbreds will venture to follow these renegades into the
penetralia of their strongholds. Sergeant Esterman, who shared the
potluck of a Cuban insurgent camp in the capacity of a gunsmith,
estimates the wild-dog population of the province of Santiago alone at
half a million, and predicts that in years to come their raids will
almost preclude the possibility of profitable cattle-breeding in
eastern Cuba.
Still, the _perro pelon_, or "tramp dog," as the creoles call the
wolfish cur, is perhaps a lesser evil, where its activity has tended
to check the over-increase of another assisted immigrant. Three
hundred years ago West Indian sportsmen began to import several breeds
of Spanish rabbits, and with results not always foreseen by the
agricultural neighbors of the experimenters. Rabbit meat, at first a
luxury, soon became an incumbrance of the provision markets, and
finally unsalable at any price. Every family with a dog or a
trap-setting boy could have rabbit stew for dinner six times a week,
and load their peddlers with bundles of rabbit skins.
The burrowing coneys threatened to undermine the agricultural basis of
support, when it was learned that the planters of the Fort Isabel
district (Hayti) had checked the evil by forcing their dogs to live on
raw coney meat. The inexpensiveness of the expedient recommended its
general adoption, and the rapidly multiplying quadrupeds soon found
that "there were others." The Spanish hounds, too, could astonish the
census reporter where their progeny was permitted to survive, and
truck farmers ceased to complain.
In stress of circumstances the persecuted rodents then took refuge in
the highlands, where they can still be seen scampering about the
grassy dells in all directions, and the curs of the coast plain turned
their attention to _hutia_ venison and the eggs of the chaparral
pheasant and other gallinaceous birds. On the seacoast they also have
learned to catch turtles and subdivide them, regardless of
antivivisection laws. How they can get a business opening through the
armor of the larger varieties seems a puzzle, but the _canis rutilus_
of the Sunda Islands overcomes even the dog-resisting ability of the
giant tortoise, and in Sumatra the bleaching skeletons of the victims
have often been mistaken for the mementos of a savage battle.
Near Bocanso in southeastern Cuba the woods are alive with capuchin
monkeys, that seem to have escaped from the wreck of some South
American trading vessel and found the climate so congenial that they
proceeded to make themselves at home, like the ring-tailed colonists
of Fort Sable, in the Florida Everglades. The food supply may not be
quite as abundant as in the equatorial birthland of their species, but
that disadvantage is probably more than offset by the absence of
tree-climbing carnivora.
Millions of runaway hogs roam the coast swamps of all the larger
Antilles, and continue to multiply like our American pension
claimants. The hunters of those jungle woods, indeed, must often smile
to remember the complaint of the early settlers that the pleasure of
the chase in the West Indian wilderness was modified by the scarcity
of four-footed game, and in the total number (as distinct from the
number of species) of wild or half-wild mammals Cuba and Hayti have
begun to rival the island of Java.
[_To be continued._]
IRON IN THE LIVING BODY.
BY M. A. DASTRE.
Iron occurs, in small and almost infinitesimal proportions, in
numerous organic structures, in which its presence may usually be
detected by the high color it imparts; and in the animal tissues is an
important ingredient, though far from being a large one. It is
essential, however, that the animal tissues, and particularly the
liquids that circulate through them, should be of nearly even weight,
else the equilibrium of the body would be too easily disturbed, and
disaster arising therefrom would be always imminent. Hence the iron is
always found combined and associated with a large accompaniment of
other lighter elements which, reducing or neutralizing its superior
specific gravity, hold it up and keep it afloat. Thus the molecule of
the red matter of the blood contains, for each atom of iron, 712 atoms
of carbon, 1,130 of hydrogen, 214 of nitrogen, 245 of oxygen, and 2 of
sulphur, or 2,303 atoms in all. Existing in compounds of so complex
composition, iron can be present only in very small proportions to the
whole. Though an essential element, there is comparatively but little
of it. The whole body of man does not contain more than one part in
twenty thousand of it. The blood contains only five ten-thousandths;
and an organ is rich in it if, like the liver, it contains one and a
half ten-thousandths. When, then, we seek to represent to ourselves
the changes undergone by organic iron, we shall have to modify
materially the ideas we have formed respecting the largeness and the
littleness of units of measure and as to the meaning of the words
abundant and rare. We must get rid of the notion that a thousandth or
even a ten-thousandth is a proportion that may be neglected. The
humble ten-thousandth, which is usually supposed not to be of much
consequence, becomes here a matter of value. Chemists working with
iron in its ordinary compounds may consider that they are doing fairly
well if they do not lose sight of more than a thousandth of it; but
such looseness would be fatal in a biological investigation, where
accuracy is necessary down to the infinitesimal fraction. The balances
of the biologists must weigh the thousandth of a milligramme, as their
microscopes measure the thousandth of a millimetre.
The great part performed by iron in organisms, what we may call its
biological function, appertains to the chemical property it possesses
of favoring combustion, of being an agent for promoting the oxidation
of organic matters.
The chemistry of living bodies differs from that of the laboratory in
a feature that is peculiar to it--that instead of performing its
reactions directly it uses special agents. It employs intermediaries
which, while they are not entirely unknown to mineral chemistry, yet
rarely intervene in it. If it is desired, for example, to add a
molecule of water to starch to form sugar, the chemist would do it by
heating the starch with acidulated water. The organism, which is
performing this process all the time, or after every meal, does it in
a different way, without special heating and without the acid. A
soluble ferment, a diastase or enzyme, serves as the oxidizing agent
to produce the same result. Looking at the beginning and the end, the
two operations are the same. The special agent gives up none of its
substance. It withdraws after having accomplished its work, and not a
trace of it is left. Here, in the mechanism of the action of these
soluble ferments, resides the mystery, still complete, of vital
chemistry. It may be conceived that these agents, which leave none of
their substance behind their operations, which suffer no loss, do not
have to be represented in considerable quantities, however great the
need of them may be. They only require time to do their work. The most
remarkable characteristic of the soluble ferments lies, in fact, here,
in the magnitude of the action as contrasted with infinitesimal
proportion of the agent, and the necessity of having time for the
accomplishment of the operation.
Iron behaves in precisely the same way in the combustion of organic
substances. These substances are incapable at ordinary temperatures of
fixing oxygen directly, and will not burn till they are raised to a
high temperature; but in the presence of iron they are capable of
burning without extreme heat, and undergo slow combustion. And as iron
gives up none of its substance in the operation, and acts, as a simple
intermediary, only to draw oxygen from the inexhaustible atmosphere
and present it to the organic substance, we see that it need not be
abundant to perform its office, provided it have time enough. This
action resembles that of the soluble ferments in that there is no
mystery about it, and its innermost mechanism is perfectly known.
Iron readily combines with oxygen--too readily, we might say, if we
regarded only the uses we make of it. It exists as an oxide in Nature;
and the metallurgy of it has no other object than to revivify burned
iron, remove the oxygen from it, and extract the metal. Of the two
oxides of iron, the ferrous, or lower one, is an energetic base,
readily combining with even the weakest acids, and forming with them
ferrous or protosalts. Ferric oxide, on the other hand, is a feeble
base, which combines only slowly with even strong acids to form ferric
salts or persalts, and not at all with weak acids like carbonic acid
and those of the tissues of living beings. It is these last, more
highly oxidized ferric compounds that provide organic substances with
the oxygen that consumes them, when, as a result of the operation,
they themselves return to the ferrous state.
Facts of this sort are too nearly universal not to have been observed
very long ago, but they were not fully understood till about the
middle of this century. The chemists of the time--Liebig, Dumas, and
especially Schönbein, Wöhler, Stenhouse, and many others--established
the fact that ferric oxide provokes at ordinary temperatures a rapid
action of combustion on a large number of substances: grass, sawdust,
peat, charcoal, humus, arable land, and animal matter. A very common
example is the destruction of linen by rust spots; the substance of
the fiber is slowly burned up by the oxygen yielded by the oxide.
About the same time, Claude Bernard inquired whether the process took
place within the tissues, in contact with living matter in the same
way as we have just seen it did with dead matter--the remains of
organisms that had long since submitted to the action of physical
laws--and received an affirmative answer. Injecting a ferric salt into
the jugular vein of an animal, he found it excreted, deprived of a
part of its oxygen, as a ferrous salt.
This slow combustion of organic matter, living or dead, accomplished
in the cold by iron, represents only one of the aspects of its
biological function. A counterpart to it is necessary in order to
complete the picture. It is easy to perceive that the phenomenon would
have no bearing or consequence if it was limited to this first action.
With the small provision of oxygen in the iron salt used up, and, if
reduced to the minimum of oxidation, the source of oxygen being
exhausted, the combustion of organic matter would stop. The oxidation
obtained would be insignificant, while the oxidation should be
indefinite and unlimited, and it is really so.
There is a counterpart. The iron salt, which has gone back to the
minimum of oxidation and become a ferrous salt, can not remain long in
that state in contact with the air and with other sources of the gas
to which it is exposed. It has always been known that ferrous
compounds absorb oxygen from the air and pass into the ferric state;
we might say that we have seen it done, for the transformation is
accompanied by a characteristic change of color, by a transition from
the pale green tint of ferrous bases to the ochery or red color of
ferric compounds.
We can understand now what should happen when the ferruginous compound
is placed in contact alternately with organic matter and oxygen. In
the former phase the iron will yield oxygen to the organic matter; in
the second phase it will take again from the atmosphere the
combustible which it has lost, and will be again where it started. The
same series of operations may be continued a second time and a third
time, and indefinitely, as long as the alternations of contact with
organic matter and exposure to atmospheric oxygen are kept up, the
iron simply performing the part of a broker. The same result will
occur if atmospheric air and organic matter are constantly together;
the consumption will continue indefinitely, and the iron will perform
the part of an intermediary till one of the elements of the process is
exhausted.