very peculiar form most people will say who remember that charcoal
and lamp-black are the common form of carbon. That one and the same
unchangeable chemical element can exist as an amorphous black lump or
powder, and also without addition or loss of chemical constituents, as
the clearest, hardest, and most brilliant of crystals, is a paradox.
The same strange capacity for existing in two totally different forms
is exhibited by other fairly familiar elements. Sulphur is found in
tertiary water-deposited clays in Sicily (it has nothing to do with
Etna or Vesuvius) in the form of clear, lemon-coloured crystals half
an inch or more in length. If you take some commercial stick-sulphur
and melt it in a porcelain spoon, and pour half the melted stuff like
treacle into a jar of water, you will find that it cools as translucent
threads which are pliable and soft. The other half which you leave in
the spoon to cool shoots out into the form of long brittle crystals
of a needle-like shape. These two varieties of sulphur are nearly as
different as lamp-black and diamond.
Diamonds are found at the Cape in a “blue ground” which is of volcanic
origin, formed by the action of steam under enormous pressure. The
blue volcanic mud has been thrust up from great depths in the earth’s
surface in the form of “pipes” 100 yards to half a mile in diameter.
It has long been known that at very high temperatures (4,000 deg.
Centigrade) the metal iron dissolves carbon. The late Professor
Moissan, of Paris, obtained artificial diamonds by suddenly cooling
the iron in which carbon was dissolved by plunging the crucible into
water. The outer shell of iron cools and forms a tightly closed shell
enclosing the still liquid core. As this core cools it tends to expand,
and thus produces an enormous pressure. The melted carbon cooling under
this pressure assumes the crystalline colourless form known as diamond.
There is good reason to believe that diamonds are formed, or have been
formed, in association with metallic iron in a similar way, on a large
scale, in great depths of the earth’s crust, and are shot up to the
surface with other débris in the volcanic steam mud which is the “blue
ground.”
A few diamonds of small size have been found in the Ural Mountains,
otherwise they are not natural products of the northern hemisphere. It
is in India, Australia, South America, and South Africa that they are
picked up, either in beds of streams, or in peculiar volcanic mud, or
embedded in even harder rock. Many are in a condition of severe strain
when found, and contain minute cavities filled with liquid carbonic
acid. They are liable, in consequence, to break or even fly into
powder when warmed by the hand or struck. Though usually colourless,
diamonds may be yellow, green, blue, or red, and the rays of radium
cause colourless diamonds to become coloured. Some diamonds, but not
all, are phosphorescent--that is to say, like the well-known luminous
paint--after exposure to strong light they acquire the power of shining
themselves for a certain time when removed to a dark chamber. And the
curious thing is that, though themselves colourless, some give out
blue, some green, some yellow, and some red light. The most wonderful,
however, in this respect are the rare diamonds which become luminous
merely by rubbing, and leave phosphorescent streaks on the cloth with
which they are rubbed. This property is similar to the phosphorescence
shown by other kinds of crystals when heated or when simply fractured.
Diamonds are readily distinguished from paste by the Röntgen rays,
since they are transparent to those rays, whilst paste (or glass)
is opaque to them. Radium also causes diamonds, but not paste, to
phosphoresce. All diamonds are not equally hard, though they are the
hardest of stones, and harder than steel, but not harder than the metal
tantalum. Some Australian diamonds are known (from Inverel, New South
Wales) which are so hard that at one time they could not be cut and
polished; but only four years ago the rapidity of the wheels used in
these processes was greatly increased, and these terribly hard diamonds
were brought into subjection.
Thus it is clear that there are many extraordinary features of interest
about the diamond, and that its brilliance and high price constitute
only a small part of its fascination.
10. _Science and Fisheries_
Science, the knowledge of the vast system of orderly, inexorable
activities under which we exist, and of which we, and all that we
can apprehend, are but more or less significant parts, is not only
to be regarded as a gratification of our curiosity, as food for our
imagination, and the basis of our philosophical theories. It is, in
addition to these, a thing of unparalleled importance to the immediate
daily welfare of every man, woman, and child, and upon its due
cultivation and use depend the future welfare, even the existence, of
whole races of mankind. It is a startling fact that so few of those
who undertake to lead and to legislate for the people of this country
have any real conviction, or even a dim understanding of this truth.
In November 1906 a Committee appointed by the Government took evidence
as to the desirability of continuing the international investigation
of the North Sea, upon which Great Britain entered five years ago
in conjunction with other Northern States. Only a few weeks before,
a number of scientific experts engaged in this study of the North
Sea, with a view to gaining such knowledge of that great “waste of
waters” as may help the nations of adjacent lands to draw from it
stores of food without destroying the source or recklessly injuring
the supply, were entertained at dinner, at the Guildhall, by the City
Fathers, and treated to speeches by hereditary legislators. The view
expressed by these speakers was that the interests of the great fishing
industry and of the fish trade were best understood by the practical
fisherman. Science was a “handmaid,” useful in her place, but not to
be permitted to undermine established interests and the hoary wisdom
of the practical man, her employer. A German expert of high official
position, one of the guests, took a different line. He was astonished,
even shocked, that Great Britain, the State most largely concerned in
the North Sea fisheries, should be hesitating about continuing to take
part in the international investigation. In Germany, he said, they
took a different course in such matters. Men of business and practical
legislators, when called upon to deal with an important problem, sought
first of all for scientific knowledge of the conditions in question,
as complete and thorough as possible, and then proceeded to act upon
the sure foundation gained. More knowledge, much more knowledge as to
the causes and conditions at work in regard to the life and movements
of fishes in the North Sea was needed. The work of the International
Committee must be continued, and his (the German) Government would
certainly continue to do its share of the work.
The contrast in the British and the German attitude towards science is
what is interesting in this episode. It is true that men of science
in this country have to be content to take a very modest part in
public affairs, and to allow politicians and self-styled “practical”
men to treat science as “a handmaiden”--thankful when science is
not regarded as an enemy. But they know well enough, and those who
are really “practical men” know, that science is no handmaiden, but
in reality the master--the master who must be obeyed; who alone can
give true guidance; who alone can save the State. The sooner and
the more thoroughly the people of this country have recognised this
fact, and insist upon its unqualified acceptance in practice by their
representatives and governors, the better for them and their posterity.
11. _Discoveries as to Malaria_
Recent scientific work, discovery, and application to practical affairs
of the results of discovery, in regard to three great obstacles to
human life and prosperity illustrate the vital importance to the state
of scientific research. The obstacles in question are the diseases
known as malaria, yellow fever, and Mediterranean, or Malta fever.
It is now twenty-five years since Dr. Laveran, of Paris, discovered
that malaria, or ague, is caused by a very minute parasite which
exists in the red blood corpuscles of those stricken with the fever,
and suggested that it is probably carried from victim to victim by
blood-sucking mosquitoes (gnats). Major Ross, of the Indian Army, who
has been rewarded for his discovery by the Nobel prize, determined to
find out what gnat it is which carries the malaria-germ from man to
man, and by most persevering experiment and microscopic examination
showed that it is not the commoner gnat or mosquito (Culex), but the
spot-winged kind (Anopheles), which alone can spread the malarial
infection. But Major Ross is, before everything else, a medical man,
and his great purpose has been to apply his discovery to the prevention
of disease.
Whole regions of the earth’s surface are rendered dangerous, or even
uninhabitable, for civilised men by malaria; in other words, by
the Anopheles mosquito. Accordingly, Ross set to work to find the
best means of destroying these agents of disease. He found that the
Anopheles gnat breeds in natural collections of water lying upon
the surface of the ground in open country, and not as many common
varieties of gnats do, in vessels and cisterns in houses. The pools
frequented by the malaria-carrying gnat are small and easily drained.
The obvious direction of science, therefore, was to remove or to cover
up these pools wherever they were found in the neighbourhood of human
habitations. Although Major Ross made his discoveries in India, and
although he opened a campaign against malaria by removal of surface
pools in the Colonies of West Africa--“the white man’s grave”--twice
visiting the chief British settlements--only half-hearted, incomplete
measures have been taken, insufficient funds have been expended, and
a supine executive and half-incredulous officials have failed to do
more than partially reduce the prevalence of malaria in those regions.
On the other hand, where intelligent officials have understood and
accepted the clear results of science in regard to malaria, the most
striking and satisfactory consequences have followed.
At Ismailia, on the Suez Canal, malaria was almost universal; in 1866
there were in a population of eight thousand, 2,300 cases. In 1897
there were over 2,000, and in 1902, when Ross was asked by the Prince
d’Arenberg to visit the place and advise as to measures to be taken,
there were 1,551 cases. Ross directed the filling up of the breeding
pools. The marshes were filled up with sand, the irrigation channels
were deepened or treated with kerosene oil (which spreads as a fine
film, and chokes the gnat larvæ), and the cess-pits were rendered
uninhabitable by chemical treatment. In one year the cases of malaria
fell to 214, in 1905 they were only thirty-seven, and now the Suez
Canal Company officially reports, “all trace of malaria has disappeared
from Ismailia.” The same satisfactory results have been obtained in
Port Said, in Khartoum, in Port Swettenham of the Federated Malay
States, in Havannah City, in Panama, and, in fact, wherever intelligent
conviction has led to the active and complete employment of the
methods necessary for the destruction of the gnats. Under the British
Government of India and the African and West India Colonies, little has
been done. Why? Because of the handmaiden theory and the ostrich-like
refusal of our officials to face and accept the master.
An even more wonderful and beneficent result has been obtained in the
case of that terrible disease “Yellow Jack,” or “Black Vomit”--the
yellow fever. Owing to the discoveries and definite proof by Ross as
to the part played by gnats in malaria, the able medical men in the
public service of the United States of America have thoroughly examined
experimentally the mode of infection of human beings with the germ of
yellow fever, and have conclusively proved that infection is solely
and entirely due to the bite of one species of gnat--the Stegomyia
fasciata. They have proved to absolute certainty that yellow fever
is not carried through the air, nor by food or drink, nor by contact
with infected persons or their cloths or emanations, but only by the
fasciate gnat, a house-frequenting species, which sucks the blood of
a yellow fever patient, and after twelve days, and not till then,
becomes capable of imparting the infection to those whom it may stab or
“bite.” The firm demonstration of this fact was not made without great
devotion, courage, and self-sacrifice. In the ardour of their pursuit
not a few of the experimenters risked and lost their lives. Among these
the name of Dr. Lazear, of the United States Army, is prominent. He
deliberately permitted himself to be bitten by a stray mosquito in a
yellow fever hospital, in order to show that the insect could convey
the infection. He was bitten on Sept. 13, 1900, and died on Sept. 25,
having proved his point.
The actual germ, microbe, or minute parasitic organism which causes
yellow fever, and is carried by the fasciate gnat, has not yet been
detected. Nevertheless, without seeing and isolating the microbe, the
medical men of America (Sternberg, Finlay, Carroll, and others) have,
by destroying the gnat and preventing its access to men--especially to
patients already infected, and, therefore, certain to infect the gnats
and cause them to spread the disease--practically made an end of yellow
fever in many great cities of the New World, where it was only six
years ago an ever-present horror, striking men down with a suddenness
and with a deadliness which paralysed human activity. Here, as in other
cases, intelligent appreciation of the results of science by a governor
or a municipality has saved thousands of lives. On the other hand, in
Rio de Janeiro, “the opposition encountered by the sanitary authorities
of the city from political factions and the ridicule to which they
were subjected by the local Press” were insuperable (I quote from an
official report), and so a few more thousand lives were sacrificed
before the master was recognised and the proffered safety accepted. In
Vera Cruz, in New Orleans, and in Panama yellow fever has been reduced
to a vanishing quantity by removing the pools and tanks in which the
fasciate gnat can breed, and by making use of wire-gauze to prevent
the access of mosquitoes to houses, bed-chambers, drains, and baths,
and especially to prevent not only their access to, but their egress
from, the rooms and beds of patients already infected with disease.
In the city of Havannah, during the American occupation of Cuba
(1900-1903), Colonel Gorgas reduced the death-rate due to yellow fever
from an annual average of 751 to so small a figure as six. The same
energetic and faithful administrator has been at work, with even more
remarkable results, in the canal zone of the Isthmus of Panama since
1904. The attempt of the French to cut the canal was foiled chiefly by
yellow fever and malaria. It is estimated that their effort cost quite
50,000 lives. Assisted by an able and enthusiastic staff, and charged
with the task by a Government which comprehends the fact that the
really “practical men” are the men who recognise science as the master
(not as the negligible eccentric handmaid), Colonel Gorgas has banished
the mosquito from his zone of occupation. As a consequence there is
neither malaria nor yellow fever on the Panama works. In 1906 the total
death-rate amongst 5,000 white employés on the Panama Canal works was
only seven in the thousand. Further, in last April the daily sick-rate
of the total force of about 40,000 people was only seventeen in the
thousand. Colonel Gorgas declares that there is but little sickness of
any kind among the Americans in the employ of the Panama Commission,
and that they and their wives and children are fully as vigorous
and robust in appearance and in fact, as the same number of people
in the United States. There is no reason why the centres of wealth,
civilisation, and population should not again be in the tropics, as
they were in the dawn of man’s history.
12. _Malta Fever_
Mediterranean or Malta fever was for long confused with typhoid and
other fevers. Our soldiers and sailors at Malta, Gibraltar, and
Cyprus, as well as many frequenters of the African and Asiatic shore,
were subject to this disease, and often incapacitated by it. In 1887
Colonel David Bruce discovered in the blood of patients the minute
Micrococcus melitensis, which is its cause, and established the fact
that it is a definite independent disease. The hospital at Malta has
received as many as 624 patients in a year suffering from Malta fever
from among the 8,000 soldiers on the island and the 12,000 sailors on
the Mediterranean Station. And as they stay in hospital on an average
for four months, this means 74,880 days of illness. This means a
considerable loss to the State, as well as a large amount of personal
suffering terminated, in some cases after two years’ sickness, by death.
The War Office, Admiralty, and Colonial Office applied in 1904 to
the Royal Society of London to undertake a further investigation of
this disease. The society sent out a small commission, which has
been at work for three years, and has published seven volumes of
reports. The problem before the commission was to discover the mode of
infection by the Malta-fever germ (the Micrococcus melitensis), and
thus, if possible, to arrive at a means of arresting the infection.
Various hypotheses, guesses as to probable and possible methods of
dissemination, were entertained and examined. As the germ occurs in the
blood, it was naturally considered possible that gnats or other insects
were the carrying agent. But negative results followed all experiments
in this direction. Then it was found that the “germ” passes out of the
body in large quantities by the renal secretion, and it was thought
that it might be conveyed in a dried form with dust in the air. This
also proved to be an incorrect supposition.
Next a very important discovery was made. The germ was found in the
blood and the excretions of 10 per cent. of the goats which are kept in
Malta as the sole source of milk, and are driven through the streets to
supply customers, whilst 50 per cent. of the goats were found to have
been infected at some time. Then the germ was found in the milk itself,
and it only remained to prove by experiment that it was from the goats’
milk that human beings acquire the infection. A monkey fed with the
milk of an infected goat acquired the fever.
The next step was to stop the consumption of goats’ milk by the
soldiers and sailors in the hospital and barrack. Actually we were
carefully feeding our invalid soldiers and sailors in the great
hospital at Valetta with a highly poisonous infected fluid--the milk
of the Maltese goat! The preventive measure--the stoppage of goats’
milk--only came into operation in July, 1906. In the first six months
of that year there were thirty-one cases of Malta fever in every
thousand of the garrison (numbering about 8,000 men). In the preceding
six months there had been forty-seven cases per thousand. Now when the
goats’ milk was stopped after July, 1906, what was the result? From
July to December, 1906, there were only ten cases per thousand of the
garrison. In actual numbers there were in July, August, and September
in 1905 as many as 258 cases, whilst in the same months in 1906, after
removal of goats’ milk from the dietary of the troops, there were
only twenty-six cases, and these were probably due to the independent
purchase of goats’ milk by soldiers outside the barracks. In the naval
hospital until 1906 almost every patient who remained in the hospital
a few weeks took the disease. Since the exclusion of goats’ milk not a
single case has occurred.
The Director-General of the Medical Department of the Navy reports
that there has been no case of Malta fever during the year among the
sailors, and only seven cases among the soldiers up to the end of
September, 1907.
Gibraltar had a fever of its own, identical with Malta fever. It has
now been shown that it was probably introduced by the importation of
goats from Malta for the supply of milk. This is likely, because the
importation of Maltese goats ceased in 1883, and the fever began to
disappear from Gibraltar in 1885, and finally vanished altogether in
1905.
In South Africa Malta-fever is common amongst the white population.
It is probable, according to Colonel Birt, that it was introduced by
means of infected goats imported from the Mediterranean. The soldiers,
however, in South Africa are free from this disease, excepting those
who have already contracted it in the Mediterranean, since in South
Africa goats’ milk does not enter into the dietary of the soldier. It
is the civilian population which suffers.
13. _A Cure for Sleeping Sickness_
Diamonds and sleeping sickness are both special African problems. It
was owing to the proposal to employ natives from Uganda in the South
African diamond mines that the Colonial Secretary (Mr. Chamberlain
at that date) asked the Royal Society to say whether the sleeping
sickness which had broken out with terrible violence in Central Africa
constituted an obstacle to that employment, on account of the danger of
introducing the disease into South Africa. The Royal Society advised
the Government not to allow the transport of natives from the infected
districts of Uganda, and sent out a commission to Central Africa to
study the disease. The result was the discovery by Colonel Bruce of
the parasite of sleeping sickness called Trypanosoma--a kind previously
known in some other diseases--and of the fact that it is a tsetse-fly
which carries it. A quarter of a million natives have died in Central
Africa within the last six years from sleeping sickness. The Tropical
Diseases Committee of the Royal Society has started an inquiry into the
action of drugs on the parasites (known as trypanosomes) which cause
sleeping sickness and the horse and cattle disease of the “fly-belts”
of South Africa.