Chapter II: Part 2

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.

The minute parasites which cause Malta, yellow, and malarial fever, and other infections, are no doubt best dealt with by excluding them from access to the human body when that is possible. But once they have effected a lodgment and commenced to multiply in the blood or tissues, it is still possible to get at them by means of drugs, which poison them without injuring their human victim. Thus quinine has been of enormous service in checking the ravages of the malaria parasite, and really in Great Britain has exterminated “ague,” which is the English name for malaria. Many experiments have been made during the last two years, with the view of finding some drug which will, in like manner, destroy the trypanosomes which have established themselves in the blood and lymph-passages of the human body, and are slowly killing their victim with sleeping sickness. An arsenic compound, “atoxyl,” has been found effective when injected into the patient’s body, and according to Dr. Koch, who returned last year from Uganda, he has found nothing better than this treatment, discovered by Dr. Thomas and Dr. Breinl, of the Liverpool School of Tropical Medicine, three years ago. Dr. Plimmer and Dr. Thomson, who have been experimenting in London for the Royal Society, have found a drug which is more effective than atoxyl in destroying certain trypanosomes which attack rats, and is now being tried in the treatment of sleeping sickness. This is the tartrate of sodium and antimony--a salt corresponding to the well-known tartar emetic, with this difference, that it contains sodium instead of potassium. It seems that this sodium variety of tartar emetic is very destructive to trypanosomes in the blood and lymph, and has no injurious effect of a lowering nature, such as occurs when the potassium salt is used. As the antimony drug is far cheaper than atoxyl, it will be possible to apply it freely to horses and cattle suffering from “nagana” and “surra,” which are diseases due to trypanosomes of a special kind. Two white men who had become infected by the trypanosome of sleeping sickness in West Africa have been treated with the new drug in London, and the parasites have completely disappeared from their blood in consequence, though it remains to be seen whether a permanent cure has been effected. One cannot imagine a situation of more thrilling interest than that existing in the nursing home where those two victims were given a strong hope of escape from what seemed to be certain death, whilst the fate of thousands of African natives, similarly infected, was hanging in the balance! After six months from the date of treatment the report is satisfactory. The parasites have not yet re-appeared (July, 1908) in the two patients treated in November.

14. _Tsetse-Flies and Disease_

Dr. Koch appears to have been questioned on his return to Europe by some journalists as to the results of his study of sleeping sickness during the past year and a half in Uganda. It was already known (three years ago), from the observations of Professor Minchin, Dr. Gray, and Dr. Tulloch (the Royal Society’s observers in Uganda), that the tsetse-fly in Uganda sucks the blood of crocodiles, also of fishes and of hippopotami. Dr. Koch confirms this observation. Minchin also observed a trypanosome in the blood of the crocodile differing from that of sleeping sickness. Whether crocodiles help, in an important degree, to keep tsetse-flies alive in the regions where they occur, by offering them a ready meal of blood, is uncertain. So far as the facts are known, they do not lead to the belief that the crocodile is a “reservoir host” for the trypanosome of sleeping sickness.

“Reservoir-host” is a very useful and expressive name for animals which can tolerate or support a parasite in their blood which is deadly to other animals. The parasite flourishes in abundance in the reservoir-host with entire satisfaction to both host and guest. But a blood-sucking fly or gnat, of promiscuous tastes in the matter of blood, comes along, sucks the reservoir-host a bit, and then goes off for another meal to a susceptible animal, into which it introduces the parasite now adhering to its already blood-smeared proboscis or beak. Such a history was first established by Bruce in regard to the trypanosome parasite which causes the deadly nagana disease in the “fly-belts” of South Africa. The big game animals are reservoir-hosts to this parasite, from which they are carried by the tsetse-fly to horses, mules, and dogs, which, being of foreign origin, are not tolerant of it, but are killed by the poison to which its multiplication in their blood gives rise. Thus, too, native children, both in Africa and the East Indies, appear to be tolerant of the malaria parasite, and act as reservoir-hosts from which the spot-winged gnats suck and distribute the parasite to the non-tolerant, susceptible adult natives and white men.

The tsetse-flies are little bigger than the common house-fly, and bite, or rather stab, very rapidly after alighting on the skin. The study of flies and gnats, and other blood-sucking insects, has become extremely important, and has been carried on with great energy by many specialists since it became known that these insects play such a terribly important part in the causation of disease. At the Natural History Museum I received (in response to a circular issued at my request by H.M. Government) thousands of specimens of gnats (mosquitoes) from all parts of the world, and some hundreds of new species have been described in a series of volumes by Professor F. V. Theobald, published by the trustees. Other volumes are in preparation illustrating the blood-sucking flies of various regions of the world, and one concerning those of the British Islands has already appeared. The common gnat, the spot-winged gnat, and the tsetse-fly--as well as the microscopic parasites causing malaria and sleeping sickness--are illustrated by greatly enlarged models--very carefully executed under my direction, which are exhibited in the central hall of the museum.

It is a curious fact that the coloured races of men--especially those of Africa--have little or no objection to being bitten by flies. They seem to accept the attention of flies and ticks with indifference. The men sleep in the day under trees, and are willing food-supply to the insects. The eyelids of children are literally inhabited by flies in some countries, and the folds of the skin of fat adults hide whole rows of fast-holding ticks. But the white man does not willingly permit either fly, flea, or gnat to settle on him. He is (or has been), nevertheless, unwisely tolerant of house-flies in his habitations, and the poorer and less cleanly population are in large proportion infested with wingless insects. The newly established knowledge that certain flies (glossina or tsetse-fly) are the carriers of sleeping sickness, that gnats are the carriers of malaria and of yellow fever, that fleas are the carriers of the plague, and that certain kinds of ticks are the carriers of cattle-fevers and dog-fevers, and probably of some obscure fevers of man, must make us all more anxious than we were about contact with insect life. For ages popular tradition has ascribed diseases of one kind and another in various parts of the world to the bites of flies. But actually it is little more than fifty years ago since it was really shown that deadly germs or parasites existed which could be, and actually are, carried by flies from one animal to another, and introduced into the blood by the flies’ stab. This was first shown in regard to the bacterium of splenic fever (or anthrax, or wool-sorters’ disease), a blood-disease of cattle which is transferred by the big, fiercely-biting “horse-flies” (tabanus), from animals to man, and is invariably fatal. Another bacterial disease, “pernicious œdema,” is inflicted on man in the same way. These cases were exceptional, and it is only quite recently that the agency of flies and fleas in great epidemics, and in diseases causing thousands of deaths every year in well-known regions, has been discovered.

15. _Monkeys and Fleas_

The wingless parasites known as pediculi are not known as active agents in spreading disease germs, probably because they do not readily transfer themselves from one animal to another. It is in this connection a really remarkable fact that monkeys are not infested by fleas, and that only in few cases and not in many kinds have pediculi or acari been observed. In this respect the lower races of men (and even the higher) seem to have fallen away from a grade of excellence attained by their despised quadrumanous cousins. When this fact as to the freedom of monkeys from insect parasites is mentioned, those who have watched monkeys in captivity will immediately say, “Surely I have seen monkeys carefully picking insects from one another’s fur.” The fact is that it is this very habit of “picking” which prevents monkeys from harbouring fleas. Whereas a dog or a cat can only scratch, the monkey has an opposible thumb and delicately sensitive fingers. That which has become the hand of man, with all its marvellous skill and efficiency, has been elaborated in its early stages as a means for keeping the hair clean. When monkeys are seen carefully removing something with finger and thumb from their own or their companion’s hair, it is not an insect but a little piece of fatty secretion and scurf which is thus removed. The habit, which seems to be general in all kinds of monkeys, even with the anthropoids, such as the chimpanzee and the orang, has of course been efficient in removing any parasitic insects which may at one time have infested monkeys--all other furry animals are liberally supplied with them, as also are birds--but is now preventive of any re-establishment of such visitors. The popular judgment of the monkey’s habit is similar to that of the Japanese Aino, who remarked to a traveller who arranged to have a bath in his room every day that he must be a very dirty man to require it.

16. _The Jigger Flea_

One flea is recorded as having been once taken on an anthropoid ape (a gorilla), and is the “jigger,” Pulex penetrans. This is a very serious pest, the history of which shows how man himself opens up the path by which dangerous diseases spread. The jigger-flea was originally known only in the South American tropics. It spread from there to the West Indies in the last century. It burrows into the skin, usually between the toes, but elsewhere also, and causes an abscess and sore as big and deep as a hazel-nut. Several such cavities at a time are dangerous, and often lead to blood-poisoning and death. Europeans avoid the burrowing of the jigger by having their toes carefully examined every morning, but black men are less careful. From the West Indies, about thirty years ago, the jigger was carried in ships to West Africa. There it flourished and spread from village to village across Central Africa, decimating the population. It appears to have been carried to a large extent by dogs, in whose skin it flourishes. It has now passed through Africa to India, and we shall no doubt soon hear of its having completed the circuit of the globe.

A great many kinds of fleas are known, many furry animals having their own special species, which does not leave them to take up its dwelling on other kinds of animal. The common rat has a large flea of its own, which apparently is not the flea which carries the plague from rats to men. It is a “wandering” flea which does this, namely, the Cheops flea. This flea, common in the East but unknown in colder regions, does not stay as one could wish it to do--on the rat; but travels about visiting human beings and dogs, and so carries the plague bacillus from rats to men. In the absence of these fleas plague would be a rat-disease unknown in men. It is probable that we do not nowadays live so thoroughly cheek-by-jowl with rats in Western Europe as formerly, so that even if rats infected with plague and harbouring the Eastern Cheops flea arrive in our docks, the wandering flea is too far off to reach us in our modern houses.

17. _Public Estimate of the Value of Science_

The Royal Society, the full title of which is The Royal Society of London for the Promotion of Natural Knowledge, has its anniversary meeting and dinner on St. Andrew’s Day. The health of the medallists of the year 1907 was given from the chair by Lord Rayleigh, and they replied one by one to the toast. Professor Michelsen, of Chicago, received what is considered the greatest honour the society has to bestow--the Copley Medal (founded more than two hundred years ago) for his researches on light. He related in his speech how he had tried to interest a wealthy business man in the experiments going on in his laboratory, in the hope that his friend might be moved to give pecuniary aid for the provision of new apparatus. One by one, he showed his delicate instruments and explained their uses; no impression was produced. At last he explained how the bright lines of the spectrum of flame, coloured by incandescent elements (such as theatre-goers know as red fire, green fire, blue fire, &c.), can be recognised by means of the spectroscope in the light of the sun--proving the presence of the metals and other elements of this earth in that remote body. He especially explained and showed his friend the experiments by which sodium, the metal of which caustic soda is the “rust,” is thus proved to be present in the sun. At last his friend spoke. He said: “Who the ---- cares if there is sodium in the sun?” Professor Michelsen did not tell the fellows of the Royal Society how he replied to that abrupt inquiry.

A more encouraging speech was that of Lord Fitzmaurice, the Under-Secretary of State for Foreign Affairs, who replied to the toast of the guests. He declared, in so many words, “It is every day becoming more and more certain that science is the master.” He said that in his own business as a diplomatist he found that the chief matters which he had to discuss and decide depended on scientific knowledge and the information and guidance given to him and his colleagues by scientific men. In the beginning of the eighteenth century the British Government had sent a bishop and a poet to negotiate the Treaty of Utrecht. But neither would be of any use in modern diplomacy. What they always had to seek at the present day was the aid of the scientific departments of the Navy or the Army, or of the Royal Society. Such matters as the relative merits of a Channel tunnel or a Channel ferry, the limitations of territory by land, by sea, or above the land in the air, the international agreements as to measures for checking the spread of disease or of insect pests, and, indeed, most matters which had come before him since he had been in office, had to be decided by the scientific experts. He did not propose that diplomatists should at once vacate their posts and endeavour to secure the occupation of them by men of science, but he thought that at no distant date such a course would be considered not only reasonable, but necessary!

18. _The Common House-fly and Others_

The common house-fly is not so innocent as he looks, but really a dirty little thing. He has not a sharp beak-like proboscis, and cannot stab, but he has a soft, dabbing proboscis, which he pushes on to every kind of filth as well as walking with his six legs on such matter. Then he comes and wipes off minute particles and germs on to our food, our lips, our fingers, and faces. It is quite certain that he, and others allied to him, are thus the means of spreading typhoid fever in camps where there are open latrines and open larders and mess tables. The house-fly breeds from a maggot, just as the blue-bottle or blow-fly does, but very few people have ever seen or recognised the maggot of the house-fly. The reason is that it lays its eggs in horse dung, and the grubs are hatched in the muck-heaps of stables. That is also the reason why it is much less numerous in London than it used to be, since stables and mews are now fewer and cleaner than they were. It is also the reason why the house-fly abounds in ill-kept country inns and farmhouses. Its breeding ground is just outside the window.

There is not only one common house-fly in this country: there are three kinds, in addition to the blue-bottle or blow-fly, which is distinguished at once by its great size and blue colour, and lays its eggs in carrion. Late in the year you may often see what would pass for young or starveling house-flies going about among the others. This is a distinct species, the Homalomyia canicularis of entomologists. The third kind only to be distinguished by careful examination with the aid of a magnifying glass, is Anthomyia radicum. Both these are much less abundant than the common house-fly (Musca domestica), with which they almost always occur. Their breeding habits are similar to those of the common house-fly.

A fourth kind of fly is invariably mistaken for the common house-fly when it is noticed, as it sometimes is, in consequence of the sharp stab which it inflicts. As recently as the beginning of November last year I was “bitten” or pricked by one of this fourth kind in a London club. They are common enough on the sea shore in autumn, and may be a severe nuisance. People generally take them for common house-flies which have lost their temper in the hot weather and give way to the bad habit of “biting” out of sheer exasperation. Really, of course, a house-fly could not stab or prick with its broad-ended proboscis. The fly in question, which looks almost exactly like a well-grown house-fly, but possesses a sharp and business-like beak or proboscis, is known to scientific men as Stomoxys calcitrans. There are many kinds of Stomoxys scattered all over the world, and it is probable, though not actually proved, that they carry parasites such as the trypanosomes of horse and cattle diseases from one animal to another, as do the species of Glossina or tsetse-fly.

But we have yet to learn more about these flies and the parasites they transfer. In the case of the gnat, it has been discovered that the malaria parasite is swallowed by the gnat, and multiplies in it, producing thousands of spores in its blood, and it is these spores which the gnat hands or rather “mouths” on to man. No such multiplication of the trypanosome in the tsetse-fly (Glossina) is known. The tsetse-fly passes on the trypanosome as it received it, and yet it seems as though it is not any and every biting fly which can pass on the trypanosome of nagana, or of sleeping sickness, but only the particular species of tsetse-fly. Perhaps it is a case of greater abundance, the tsetse-flies being the obvious and dangerous carriers of trypanosome disease where they occur, on account of their abundance and the fierceness and celerity of their attack. It is almost certain that in India, Burma, and South America some other flies must transfer the trypanosomes from animal to animal, causing the diseases known as surra and mal de caderas, because no tsetse-flies--that is to say, no flies of the genus Glossina--occur in those countries, and no other mode of transference, except by some blood-sucking insect, seems probable.

Ants in Africa are carriers of infection, and possibly also in London kitchens, where a little red ant sometimes abounds. The black beetle or cockroach is a creature to be got rid of, as it is very probable that it spreads certain kinds of infection over food and dishes during the hours of “revelry by night” which kind-hearted people allow it to enjoy in their kitchens.

19. _Cerebral Inhibition_

The best golf-player does not think, as he plays his stroke, of the hundred-and-one muscular contractions which, accurately co-ordinated, result in his making a fine drive or a perfect approach; nor does the pianist examine the order of movement of his fingers. His “sub-liminal self,” his “unconscious cerebration,” attends to these details without his conscious intervention, and all the better for the absence of what the nerve-physiologists call “cerebral inhibition”--that is to say, the delay or arrest due to the sending round of the message or order to the muscles by way of the higher brain-centres, instead of letting it go directly from a lower centre without the intervention of the seats of attention and consciousness. The sneezing caused in most people by a pinch of ordinary snuff can be rendered impossible by “cerebral inhibition,” set up by a wager with the snuff-taking victim that he will fail to sneeze in three minutes, however much snuff he may take. His attention to the mechanism of the anticipated sneeze, and his desire for it, inhibit the whole apparatus. So long as you can make him anxious to sneeze and fix his attention on the effort to do so, by a judicious exhortation at intervals, he will not succeed in sneezing. When the three minutes are up, and you both have ceased to be interested in the matter, he will probably sneeze unexpectedly and sharply. I was set on to this train of thought by a recent visit to an exhibition of photographs.

There were many very interesting illustrations of the application of photography to scientific investigation. Among others I saw a fine enlarged photograph of the common millipede (Julus terrestris), and my desire was renewed to have a bioscopic film-series of the movements of this creature’s legs. Some years ago I attempted to analyse, and published an account of, the regular rhythmic movement of the legs of millipedes. I found that the “phases” of forward and backward swing are presented in groups of twelve pairs of legs, each pair of legs being in the same phase of movement as the twelfth pair beyond it. But instantaneous photography would give complete certainty about the movement in this case, and in the case of the even more beautiful “rippling” movement of the legs of some of the marine worms. Some kindly photographer might take up the investigation and prepare a series of films. The problem is raised and the effects of “cerebral inhibition” described in a little poem which I am told we owe to the author of “Lorna Doone.” As it is not widely known, I give it here as a record of “cerebral inhibition”:

“A centipede was happy ’til
One day a toad in fun
Said, ‘Pray which leg moves after which?’
This raised her doubts to such a pitch
She fell exhausted in the ditch,
Not knowing how to run.”

The point, of course, is that she could execute the complex movement of her legs well enough until her brain was set to work and her conscious attention given to the matter. Then “cerebral inhibition” took place and she broke down.

20. _Colour-photography and Photographs of Mars_

There were admirable photographs of wild birds and their nests, and of insects and plants in this exhibition. I saw the new Lumière coloured transparent photographs thrown by a lantern on the screen, and could distinguish the dots of red, green, and violet colour on what, at a little distance, appeared to be a brilliantly white part of the picture (the shirt collar of a “sitter”), just as one sees a mosaic of coloured dots in the blazing sunlight of the pictures painted by the French school of so-called “vibristes” (Monod and others). Perhaps the most remarkable of these photographs was a set of prints from untouched photographs of the planet Mars, executed in July 1907 by Professor Perceval Lowell at his observatory in Arizona.

The Mars photographs are each about as big as a dried pea (that is the biggest size possible with the feeble light reflected by Mars), but “several of the canals,” says Mr. Lowell, “are distinctly visible on the photographs, and one has been photographed double.” I should have liked to examine these photographs in a good light with a lens. The statement quoted means that the canals in Mars can no longer be regarded as due to errors of eyesight and imagination, and that the annual doubling or formation of a second canal parallel to what was earlier in the year a single canal, is actually recorded by a disinterested, impartial photographic plate. Are these canals the work of intelligent inhabitants of Mars? I will not venture to say in reply more than this, that I have never heard any other explanation of their occurrence. But that, of course, still leaves the matter open.

21. _Origin of Names by Errors in Copying_

A curious illustration of a mistake perpetuated by a clerical error is the title of Viscount Glerawly. The title was intended to have been Glenawly, but the bad writing of a clerk converted the “n” into an “r,” and the name having been so entered in the patent of nobility, or some such document, could not be altered. The same thing has happened to the mammoth. His proper native name is “mammont,” but “mont” became “mout,” and then “moth.” A similar clerical error is responsible for the name Gavial, which is applied to the long, narrow-nosed crocodile of India, both as a scientific name (Gavialis) and colloquially. Really the “v” is due to a misreading of an “r,” the creature’s native name being Garial. It was so written down and sent home by an early explorer, but his handwriting being wanting in clearness, the word was copied as Gavial and the scientific patent issued in that name.

22. _False News as to Extinct Monsters_

The tendency of English newspapers to bedeck themselves every now and again with rank absurdities copied from American rubbish-sheets is a disease. On no subject outside the field of natural history and medicine would any editor dream of printing the stuff which does duty as “news” in regard to these departments--stuff which has not even the semblance of being carefully concocted, but yet is found “good enough” to circulate as serious information.

Another antediluvian monster, much larger than the mammoth, was reported in a London evening paper at the end of November 1907. The article devoted to it is a mass of absurdity, a burlesque of a genuine note on the subject. It appears that the most ordinary thing happened at Los Angeles, California, namely, that some workmen, in driving a tunnel, unearthed some fossil bones. We are not surprised to learn (though it is announced as a marvel) that the bones were those of a mastodon (of which you may see a whole skeleton in Cromwell-road), and those of the extinct American elephant called Elephas columbi. This very commonplace occurrence was certainly not worth recording in a London daily paper. So it is elaborately dressed up with details intended to “fetch” the innocent reader. The writer says Elephas columbi is as much larger than the Siberian mammoth as that is larger than the horse of to-day. The truth is that Elephas columbi and the mammoth are as nearly as possible of the same size. To writer goes on to tell of a “fossil horse,” found at the same place, “a wonderful two-toed animal marked by his cloven hoof.” That is cool impudence; it is precisely “the double hoof” which none of the horse tribe possess, but all the deer, cattle, and sheep do. He next tells us that elephants and mastodons were never found together before, but supposed to have shunned each other’s company. This is an invention; their remains are found side by side all over Europe. Then suddenly the surprising statement is made, like a bolt from the blue, “England ceases to be the Mother Country and Germany the Fatherland to us,” and the pre-eminence of America in providing the biggest thing on earth is declared to have been already manifest “when the world rose out of chaos.” It is satisfactory to be told that England is not the Mother Country of this silliness; but whether the world which solemnly prints and reads it can be said to have yet “risen out of chaos” must be regarded as doubtful.

23. _Mistletoe and Holly_

Christmas things and customs comprise much that has great interest from a scientific point of view. Our modern celebration of Christmas in England is a combination of the Christian festival of the Nativity with that of the Epiphany, and that of St. Nicholas, who long ago was substituted for the sea god Neptune, of classical mythology, by sea-faring folk. Santa Claus--or Saint Nicholas--has his festival at the beginning of December, but he has been carried over to Christmas Day, and appears as “Father Christmas” in modern celebrations. There is no great antiquity about this part of the tradition which we try to keep alive at Christmas. The making of Christmas Day and Christmastide into a special children’s festival is, on the other hand, a moving back of the festival of the Epiphany, when gifts were brought to the child Christ by wise men of the East. In Rome I have assisted in celebrating our Twelfth Night under the name “Befani,” at a great illuminated public fair, near the Pantheon, where children are taken to buy toys.

There has been in England also a similar moving back of the very ancient--even prehistoric--celebrations of the New Year to Christmas, and hence it is that the mysterious and sacred “mistletoe” of the Druids is mingled in our houses with the less significant but beautiful holly as a decoration. The Christian Church, however, did not, and does not, sanction the introduction of mistletoe into the sacred edifice, and not many years ago those who loved and truly understood tradition would not permit mistletoe to be mixed with holly even in the private house at Christmastide. Mistletoe, it was held, could not be rightly introduced until the new year. The new year, however, of the Druids differed in date from that of the later calendar, and fell in what is to us the second week of March.

The holly tree, with its splendid red berries and shining, prickly leaves, is a beautiful decorative plant, very hardy and abundant: it was used by the old Romans in their “Saturnalia,” a feast which nearly coincided with the Christmas of the new religion. There is a species of holly in South America the leaves of which are made into tea by the Indians, the Paraguay tea or matté. This tea is an unpleasant, bitter decoction, devoid of aroma, if I may judge from samples which I have tasted in London. “Ilex” is the botanical name of the genus to which both our holly-tree and the Paraguay tea belong, but it must not be confused with the evergreen oak to which the name Quercus ilex is given on account of the resemblance of its leaves to those of a holly.

The mistletoe (or mistil-tan, the pale branch, in Anglo-Saxon) is a pale-coloured, small-flowered member of a great family of parasitic plants, the Loranthaceæ. They all live upon trees, and draw a part of their nourishment from the juices of the tree into which their rootlets penetrate. The tropical allies of the mistletoe are very beautiful plants, with fine bunches of brilliantly-coloured flowers and broad handsome green leaves. Our mistletoe is most commonly found parasitic on apple trees and poplar trees. It occurs on nearly all our trees, but is very rare on the oak. A careful inquiry some time ago resulted in the discovery of only seven oaks in all England on which mistletoe was growing. The Druids took their sacred mistletoe from the sacred oak tree on account of its rarity. To them it was a charm against infertility and sterility, and, according to Pliny, was cut and distributed at the new year with great ceremony and the sacrifice of heifers. Its paired white berries contain a viscid fluid which gives it its botanical name Viscum album--and causes the seeds to adhere to the beaks of birds--and thus to be transported to a distance and introduced by the birds’ attempts to wipe their beaks into the cracks of the bark of trees, in which the seeds germinate.

The white-berried mistletoe is the only English kind, and red mistletoe seems altogether out of character. But a red-berried species (Viscum cruciatum) is parasitic on the olive tree in Spain, North Africa, and Syria. Curiously enough, though the white-berried mistletoe is excommunicated by the Western Christian Church on account of its use in pagan worship, the red-berried mistletoe was gathered from olive trees in the Garden of Gethsemane and in the enclosure of the Holy Sepulchre at Jerusalem by Sir Joseph Hooker, the great botanist. The red-berried mistletoe was successfully raised from seed on young olive trees six years ago in this country by the Hon. Charles Ellis, of Frensham, near Haslemere, and was figured at that time by Hooker.

The mistletoe has an evil name in Scandinavian mythology. Baldur, the beautiful, the Sun-god, was made, like Achilles, invulnerable to spears and arrows cut from whatever tree grows on earth. All things had taken an oath not to hurt him, and the gods of Walhalla amused themselves by throwing all sorts of darts and clubs at him--none could hurt him. At last the blind god Höder, who loved the beautiful Baldur none the less because he himself was weakly and sightless, also ventured to throw a dart at his invulnerable friend. It sped home, pierced Baldur’s heart, and killed him. The dart was made of mistletoe, a tree that does not grow on earth, but lives as a parasite high up on other trees, and had taken no oath to spare Baldur. It had been put into the blind god’s hand in a friendly helpful sort of way by a designing female, who was really the evil spirit Loki in disguise. What is the allegory? Does the mistletoe dart stand for calumny? Is the mistletoe associated with calumny because it is a parasite in high places? If one must choose between the mistletoe myth of Norsemen and Briton--the latter, which survives in the power accorded to the mistletoe to license, even to command, by its mere overhead existence, the giving and taking of unexpected kisses and of expected ones, too, is certainly the more cheerful and suitable to the hopeful enterprise of New Year.

24. _The Cattle Show_