life as measured by the fulfilment of that desire, is the indication and
warrant of true greatness of character. We Englishmen have ever loved to
recognise this noble kind of devotion in our national heroes.”
VI
METCHNIKOFF AND TOLSTOI
The Darwin celebration at Cambridge, in June 1909, brought a wonderful
assemblage of celebrated biologists from all parts of the world to this
country. There never has been seen such a company of great discoverers
of all nationalities in the field of natural history and the science of
living things, as were present in the University of Cambridge during
that week. Even philosophers, moralists, and jurists were present to
join with the one great political leader of our own country who really
knows and appreciates the importance of the scientific study of
Nature—the Right Hon. Arthur J. Balfour—in his fervent and heartfelt
tribute to the influence of Darwin’s work and theory in all departments
of human knowledge, thought, and activity. One of the most remarkable
men present was Elie Metchnikoff. He represented both Russia, the
country of his birth and earlier scientific work, and his adopted
country, France, where, as sub-director of the Institut Pasteur, his
later and most important researches have been carried on. Russia was
also represented by Salensky, late director of the Museum of St.
Petersburg, well known to us all as a discoverer in the embryology
(growth from the egg) of marine animals, and by Timiriazeff, the
botanist, renowned for his work on the mode in which leaf-green or
“chlorophyll” enables green plants to obtain their food from the gases
of the atmosphere. France had other representatives in Edmond Perrier,
director of the Paris Museum, and Prince Roland Bonaparte.
Metchnikoff was one of the four representatives selected by the
University to deliver orations in the Senate House in honour of Darwin.
He especially drew attention to the influence of Darwin’s theory on the
study of disease. The recognition of the derivation of man from animal
ancestors, and of the complete community of the structure and the
chemical activity of the organs of man with those of the organs of
animals, had made (he said) the study of the diseases of animals a
necessary feature in the understanding of the diseases of man. The
far-reaching principle of Darwin that the mechanisms and processes
observed in the bodies of plants and of animals (including man) must
have been selected in the struggle for existence and perpetuated,
because of their utility, led Metchnikoff to inquire what is the value
or use of the process called inflammation and of the “eating
corpuscles,” or “phagocytes” (so named by him), which wander from the
blood into inflamed tissues. This question had led him to the discovery
that the phagocytes engulf and destroy disease-germs, and are the great
protectors of the animal and human body against bacteria and other germs
which enter cut and wounded surfaces, and would start disease were there
not “inflammation,” which is nothing more nor less than a
nerve-regulated stagnation of the circulation of the blood at the
wounded spot, and the consequent arrival at this spot of thousands of
“phagocytes,” which pass out of the stagnant blood through the walls of
the fine blood-vessels. These armies of phagocytes proceed to eat up and
destroy all the germs which fall on to the wound—from the air, from
dirty surfaces, and from the skin. The utility of inflammation and its
gradual development, according to Darwinian principles, in the animal
series, was shown twenty years ago by Metchnikoff. His important work on
“immunity” and on infection and on protection against germ-caused
disease is thus seen to be one of the many flourishing and valuable
branches of knowledge which have originated from Darwin’s great
conception and his example in experiment and inquiry.
Metchnikoff is now devoting all his attention to the possibility of
prolonging human life. The facts seem to show that if we ate and drank
only what is best for us, and led lives regulated by reason and
knowledge, we should, nearly all, attain to 80 or even 100 years of age,
having healthy minds and healthy bodies. We should die quietly and
comfortably at the end, with much the same feeling of contentment in
well-earned final repose as that which we now experience in going to
sleep at the end of a long and happy day of healthy exercise and
activity. Metchnikoff thinks that the causes of too early death may be
ascertained, and when ascertained avoided or removed. In 1870, in a
little book on _Comparative Longevity_, I distinguished what we may call
the “possible life,” or “potential longevity,” of any given human being
from his or her “expectation” of life. Potential longevity has been well
called our “lease” of life. It is probably not very different in
different races of men or individuals, and is probably higher than King
David thought, being 100 to 120 years, and not merely 70 years. We all,
or nearly all, fail to last out our “lease” owing to accidents,
violence, and avoidable, as well as unavoidable, disease; so that 70
years is named as our tenure when the injury done to us by unhealthy
modes of life and by actual disease are considered as inevitable.
Metchnikoff proposes to discover and to avoid those conditions which
“wear down” most of us and produce “senility” and “death” before we
have really run out our lease of life.
Human beings die most abundantly in the earliest years of life.
Statistics show that at birth the chance or expectation of life is only
45 years, whilst at 10 years old you may expect to live to be 61. At 30
you have not a much better chance—you will probably, if you are what is
called a “healthy” life, die when you are 65. But if you survive to be
50 you may expect, if you have not any obvious disease or signs of
“break up,” another twenty years, and will probably die at 70; surviving
to 60, you may expect, if you are what passes for “healthy,” to live to
73. Now, it is especially with regard to life after 40 or 50 years of
age that Metchnikoff is interested. Those who have survived the special
dangers and difficulties of youth, and have arrived at this mature age,
ought to be able to realise much more frequently than they do something
like the full “lease of life.” There seems to be no reason why they
should not avoid the usual rapid “senile changes” or weakness of old
age, and survive, as a few actually do, to something like 100. The
causes of “senile change” and the way to defeat their operation are what
Metchnikoff is studying. Hardening of the walls of the arteries set up
by certain avoidable diseases contracted in earlier life, and by the use
of alcohol (not only to the degree which we call “drunkenness,” but to
such a degree as to make one depend on it as a “pick-me-up”), is an
undoubted cause of that weakness and liability to succumb to other
diseases which is so general after 50 years of age. The causes which
produce hardened arteries can be avoided. Another cause of senile
changes is declared by Metchnikoff, to arise from the continual
absorption of poisonous substances produced by the decomposition of
partially digested food in the lower bowel or large intestine. This is
at present the chief subject of his study. It is to prevent the
formation of these poisons that he has introduced the use of sour milk,
prepared with the lactic ferment. Since the Cambridge celebration he has
been in London in order to examine the condition of certain patients
from whom a distinguished English surgeon has found it necessary to
remove the “large intestine.” Metchnikoff wishes to ascertain what
bacteria, poison-producing or other, are present in these patients, and
what is their general chemical condition now that this poison-producing
part of the digestive canal has been taken from them.
In Paris, Metchnikoff has some very interesting experiments in progress
with bats. He uses the large tropical fruit-eating bats, or “flying
foxes.” They have a very short intestine, and very few bacteria and of
very few kinds are to be found in its contents. On the other hand, there
are as many as thirty distinct kinds of bacteria producing putrefaction
or other chemical change in the digestive canal of man—and their
quantity is gigantic. They pervade the whole contents of the human
digestive canal by millions. By properly feeding the flying foxes in his
laboratory in Paris Metchnikoff has actually succeeded in getting rid of
all bacteria from their digestive canal, so that he now has adult
mammalian animals, not very remote from man in their structure, food,
and internal chemistry, which are absolutely free from the intestinal
parasitic bacteria which he supposes to cause poisoning and senile
changes in man. It is obvious, without pursuing the matter into further
detail here, that Metchnikoff is now in a position to test his views as
to the action of particular kinds of bacteria—he has animals which are
free from them. He can make an experiment, keeping some of his bats
still free from bacteria and causing some to be largely infected by this
or that kind, and he can compare the result in regard to the health and
chemical condition of the animals. So, too, the patients from whom the
lower intestine has been removed may very probably furnish him (through
his assistant who remains in London) with important facts for comparison
with the condition of persons who have not been deprived of this part of
the digestive apparatus.
I have given this sketch of what my friend is doing in order to furnish
some notion of the kind of investigation which he pursues. He does not
expect to extend the “lease” of human life, but by ascertaining in a
definite scientific way the true rules of internal and external
“hygiene” he does hope to give mankind an increased “expectation” of
life; in fact, to enable a vastly larger number of men and women to
enjoy that lease to the full, and to die without disappointment and
regret, even with contentment and pleasure, at the end of it.
Metchnikoff was in Russia in the spring of 1909, and spent a day with
Tolstoi. They were “fêted” and photographed together, the greatest
artist and the greatest scientist of Russia. Tolstoi is 81 years of age.
He took Metchnikoff out alone for a drive in his pony-cart so as to talk
with him without interruption. “What do you think of life?” was the
first question he asked, and one which it took my friend some time to
answer. In regard to vegetarianism the two great men did not agree. When
Metchnikoff declared that there was less cruelty on man’s part in
killing wild animals to eat them than in leaving them to die by the
tooth and claw of predaceous animals or from starvation, Tolstoi
observed that that was argument and reason, and that he paid no
attention to them; he only guided himself (he said) by sentiment, which
he felt sure told him what was good and right! He was, however, deeply
interested in an account of the cannibalism of savage races of men,
concerning which he seemed to be quite uninformed. He also was
profoundly interested in Metchnikoff’s view that Goethe, in the second
part of _Faust_, is chiefly bent upon depicting the persistence of the
amorous passion in old age—of which Goethe himself was an example—and
Tolstoi declared that this gave a new meaning to the poem, which he had
always hitherto found dull and unintelligible. But when Metchnikoff
described in glowing words the joy and even rapture with which man will
hereafter welcome the repose and mystery of death, having completed a
long and healthy life of some hundred years, Tolstoi declared that this
was indeed a fine conception, although it was entirely subversive of his
own notions as to the significance of life and death. Tolstoi also
stated that he had written his stories rapidly and without effort, but
that his essays on morality and religion had cost him great labour; and,
further, that he could not now remember the former, though the latter
still were developing and incessantly occupied his thought.
It was admitted with regret by Darwin that he ceased in middle age to
care for poetry and art, though there seems to be no doubt that he
mistook fatigue and preoccupation of mind for a real change in taste and
power of appreciation. It is interesting to place beside this the case
of the great literary artist, Tolstoi, who not only frankly confesses
that he refuses to be guided by reason and follows sentiment, but is
also profoundly ignorant upon all the most ordinary topics of human life
outside his own village, and of all Nature and her workings. Would
Tolstoi have been a greater or a smaller artist if he had had a larger
knowledge of the things that are? Was Darwin’s great scientific
achievement really related to an innate indifference to what is called
“poetry”? I will not now discuss the matter, but I am convinced that so
far as natural gift is concerned, the keenest scientific capacity is not
only compatible with the fullest sensibility to art and with the power
of poetical vision and expression, but is often accompanied by them;
and, further, that the work of an artist, if he is a great artist,
cannot be hampered by knowledge. It is only the small talent or the
feeble genius that can be paralysed rather than developed by the fullest
experience and the widest knowledge. Necessary incompatibility of mental
qualities has no place in this matter; what has led to the erroneous
assumption that it has, is the excessive exercise by exceptional
individuals of certain powers—a specialism necessary for effort and
success, but deliberately chosen, and not due to an inborn
one-sidedness.
VII
THE LAND OF AZURE BLUE
The Côte d’Azur whither many of my readers will be travelling—in
thought, if not in reality—about Easter time, is well named the Land of
Azure Blue, for it is the blueness of the sea, of the sky, and of the
distant rocks and mountains, as well as much of the vegetation, which is
when the sun shines, its special charm. And although one has some wet
and some cloudy days, yet the sun does shine there with a strength and
brilliancy not to be enjoyed in the early part of the year on the
Atlantic and North Sea coast. This tract of country, more commonly known
to English people as the Riviera, has very special meteorological
conditions owing to its position as the narrow strip of shore-line
existing between the vast mass of the Western Alps and the Mediterranean
Sea. It is warmed by the sea, and lies too close under the mountains to
be caught by any winds from the north, and at many points is also
effectively protected from both east and west winds by rocky spurs of
the great mountain chain.
The Riviera is a constant source of delight to those who love flowers
and beautiful vegetation of all kinds. But few of its visitors
appreciate the fact that it is really from end to end one big garden,
cultivated for ages by its inhabitants, and full of plants introduced by
man which at present seem at first sight to be characteristic natives
of it, but are, in reality, quite distinct from its primitive
vegetation. This primitive vegetation is now represented only in what is
locally called the “maquis”—what we should, perhaps, term the “scrub”
or “bush” in English. It comprises some pines, the juniper, the lovely
rock roses, balsams, rosemary, the giant heath (bruyère), from which our
briar-root pipes are made, the larger thyme, the myrtle, the rose of
Provence, two kinds of lavender, and many aromatic plants with grey
hairy leaves, and often provided with sharp thorns as additional
defences against browsing goats. The delicious perfumes of these hardy
inhabitants of the dry, rocky grounds, where little or no grass can
flourish, are developed by them as a protection against browsing
animals, who cannot tolerate much of these pungent volatile oils,
although mankind extracts them and uses them in the manufacture of such
scents as eau-de-Cologne and also in cookery.
Many a visitor to the Riviera never strays from the cultivated fields
and roadways into this scrub-land. The olive tree, which forms so
prominent and beautiful a feature in the panorama of gardens which
unrolls itself as we steam or drive along the coast from Toulon to
Mentone and from Mentone to Genoa and Spezzia, is not a native plant; it
was introduced in prehistoric times, and has been again and again
re-established by emigrants from Italy; but it was brought to Italy from
the East. It is astonishing how many of the cultivated trees of the
Riviera have the same kind of history—the vine came from India in
prehistoric times, the fig tree more recently from Persia, the lemon
from India, the orange and the peach tree from China. All of them were
introduced in very ancient times to the eastern parts of the
Mediterranean basin, and so gradually were carried to the shores of the
Ligurian sea, and would die out here were they not to a certain extent
under the care of ownership.
The so-called “mimosa,” so abundant here, with its pretty,
sweet-scented, yellow blossom, is an Australian acacia, only introduced
some sixty years ago; whilst the eucalyptus—a most picturesque and
effective addition to the landscape—is a still later introduction from
Australia. The cypress, that darkest and most shapely of conifers, long
lines of which proclaim to the traveller as he passes Avignon his
arrival in the true “South,” is not a native of these parts, although it
flourishes in suitable situations. It was introduced in mediæval times
from the East. So, too, the palms, though some have been cultivated for
centuries, have been largely imported from extra European localities in
the last century. There is a native European palm. It is a kind of
fan-palm, and grows here. I have gathered it in Sicily. It does not
“rear its stately head” more than a foot from the ground, and is known
to botanists as _Chamærops humilis_. The gigantic Mexican agave and the
prickly-pear cactus were introduced in the seventeenth century from the
New World, though, according to Sir Herbert Tree’s scenery, they were
growing at Cape Miseno in the time of Antony and Cleopatra! Bamboos of
many kinds have been introduced here from the Far East, and flourish
exceedingly.
The orange tree was brought from India (whither it was carried from
China) and established in Southern Europe in mediæval times, though
known to the ancient Greeks and Romans. There are as many as 120
different varieties of the orange tree now cultivated on the shores of
the Mediterranean, including, besides those which are valued for their
sweet juicy pulp, those which furnish bergamot oil and similar aromatic
products. The “issue pea” of old apothecaries, which was bound into a
cut made in a patient’s flesh for the purpose of producing inflammation
and suppuration, with the notion that such treatment was beneficial, was
a minute unripe orange dried, and, no doubt, to some extent, antiseptic.
Besides the introduced trees, we find, in ground which has been more or
less under cultivation, and not, therefore, of the nature of the
“maquis,” or scrub-land, some beautiful plants, such as the narcissus,
iris, and various lilies. One very small and graceful tulip is, I
believe, regarded as native to the soil, but a magnificent crimson
tulip, as large as the varieties cultivated in English gardens, which I
have found abundantly in open park-like land under olive trees at
Antibes, is said to have been introduced from Persia in the Middle Ages,
and to have taken kindly to the Riviera. It is the _Tulipa oculus
solis_. In the same locality were growing many brilliantly coloured
“stellate” anemones.
There is, of course, a third group or “lot” of plants on the Riviera,
which consists of those brought from all parts of the world during the
past century, and regularly cultivated and cared for in gardens. The
climate of the Riviera enables the gardener to grow all sorts of
sub-tropical plants in the open air, and a long list of them could be
given. The wonderfully brilliant crimson creeper, Bougainvillia, covers
walls by the roadways, and even the railway stations, with its rich
colour at this season. A delightful book by the distinguished botanist,
Professor Strasburger, describing and picturing in colours many of the
cultivated as well as the wild plants of the Riviera, has lately been
published (in English) at a small price.
The animals which come under the notice of those who go in search of
spring sunshine to the Riviera are far less numerous than the plants.
But there is one which is dear to all, although it makes such a noise
for an hour or so about sunset that some people are irritated or even
alarmed by it. This is the little green tree-frog, Fig. 1, which now
comes forth from its winter sleep, and assembles in thousands—guided by
the “croak” or “call” which is produced by the males. The females have a
very small voice comparatively. I kept two—a male and female—through a
winter in London, and when the spring came the male terrified the
household one night by unexpectedly uttering his cry—loud and sharp—to
which the female replied. “Wharr! biz” is the nearest expression I can
give in letters to the two sounds. After a great many evenings spent in
these rhythmical declamations, the little frogs collect round pools and
tanks, and at last drop from the trees into the water, and there deposit
their spawn. When producing his cry the male distends the skin of his
throat like a balloon. The air is driven alternately from it into the
lungs and back again over the vocal chords, which vibrate with no
uncertain sound. These little frogs are easy to keep in an inverted
bell-jar or in a fern-case, but must be fed regularly with flies and
spiders, which they catch by a sudden dab of the tongue at the moment of
alighting from a long leap on to the glass where the insect is crawling.
They can hold on to smooth glass or leaves by means of their sucker-like
toes (Fig. 1).
The colour of the upper surface of the South European tree-frog is a
most vivid and smoothly laid-on grass-green. Occasionally the colour
becomes altered to a brownish purple, but returns after a day or two to
its usual bright green tint. A great rarity is the blue variety of this
frog—the enchanted Prince of the Côte d’Azur—blue as the sky and the
sea around him—the true _genius loci_. I obtained one a few years ago
at Mentone, and kept it alive for three years in London. Its blue was
the blue of the forget-me-not or the finest turquoise. When it died (I
believe of old age, and not from discomfort or disease) I examined its
skin very carefully with the microscope, and compared it with that of
the ordinary green tree-frog, in order to make out the cause of their
difference in colour.
[Illustration: FIG. 1.—The little green tree-frog or “rainette” of the
Riviera (_Hyla arborea_). From Professor Gadow’s volume on _Reptiles and
Amphibia_—in the “Cambridge Natural History”—published by Macmillan &
Co., by whose permission this figure is here produced.]
At Mentone there is a little shop where one may purchase green
tree-frogs and ornamental cages in which to keep them. Every year the
dealer has two or three specimens of the blue variety on sale—their
backs and heads looking like bits of turquoise-blue kid. Visitors have
sometimes wrongly supposed that the blue frogs had been artificially
changed in colour, but they are real, natural varieties. A similar
substitution of blue for green has been noticed as a rare variation in
other kinds of frogs and toads in other countries. It really consists in
a suppression of yellow pigment.