On the day after Sedan the Quaker surgeon Lister had published directions for the use of aqueous solutions of carbolic acid to destroy septic particles in wounds, and of oily solutions "to prevent putrefactive fermentation from without." He recognized that the earlier the case comes from the field the greater the prospect of success.

Sedillot (the originator of the term "microbe"), at the head of an ambulance corps in Alsace, was a pioneer in the rapid transport of wounded from the field of battle. He knew the horrors of purulent infection in military hospitals, and regretted that the principles of Pasteur and Lister were not more fully applied.

After the war was over, Pasteur kept repeating his life-long exhortation: We must work--"_Travaillez, travaillez toujours!_" He applied himself to a study of the brewing industry. He did not believe in spontaneous alterations, but found that every marked change in the quality of beer coincides with the development of micro-organisms. He was able to tell the English brewers the defects in their output by a microscopic examination of their yeast. ("We must make some friends for our beloved France," he said.) Bottled beer could be pasteurized by bringing it to a temperature of 50 to 55 C. Whenever beer contains no ferments it is unalterable. His scrupulous mind was coming ever closer to the goal of his ambition. This study of the diseases of beer led him nearer to a knowledge of infections. Many micro-organisms may, _must_, be detrimental to the health of man and animals.

In 1874 the Government conferred upon Pasteur a life annuity of twelve thousand francs, an equivalent of his salary as Professor of Chemistry at the Sorbonne. (He had received appointment in 1867, but had been compelled by ill-health to relinquish his academic functions.) The grant was in all respects wise. Huxley remarked that Pasteur's discoveries alone would suffice to cover the war indemnity of five milliards paid by France to Germany in 1871. Moreover, all his activities were dictated by patriotic motives. He felt that science is of no country and that its conquests belong to mankind, but that the scientist must be a patriot in the service of his native land.

Pasteur now applied his energies to the study of virulent diseases, following the principles of his earlier investigations. He opposed those physicians who believed in the spontaneity of disease, and he wished to wage a war of extermination against all injurious organisms. As early as 1850 Davaine and Rayer had shown that a rod-like micro-organism was always present in the blood of animals dying of anthrax, a disease which was destroying the flocks and herds of France. Dr. Koch, who had served in the Franco-Prussian War, succeeded in 1876 in obtaining pure cultures of this bacillus and in defining its relation to the disease. Pasteur took up the study of anthrax in 1877, verified previous discoveries, and, as we shall see, sought means for the prevention of this pest. He discovered (with Joubert and Chamberland) the bacillus of malignant edema. He applied the principles of bacteriology to the treatment of puerperal fever, which in 1864 had rendered fatal 310 cases out of 1350 confinements in the Maternite in Paris. Here he had to fight against conservatism in the medical profession, and he fought strenuously, one of his disciples remarking that it is characteristic of lofty minds to put pa.s.sion into ideas. Swine plague, which in the United States in 1879 destroyed over a million hogs, and chicken cholera, also engaged his attention.

Cultures of chicken cholera virus kept for some time became less active.

A hen that chanced to be inoculated with the weakened virus developed the disease, but, after a time, recovered (much as patients after the old-time smallpox inoculations). It was then inoculated with a fresh culture supposed sufficient to cause death. It again recovered. The use of the weakened inoculation had developed its resistance to infection. A weakened virus recovered its strength when pa.s.sed through a number of sparrows, the second being inoculated with virus from the first, the third from the second, and so on (this species being subject to the disease). Hens that had not had chicken cholera could be rendered immune by a series of attenuated inoculations gradually increasing in strength.

In the case of anthrax the virus could be weakened by keeping it at a certain temperature, while it could be strengthened by pa.s.sage through a succession of guinea-pigs. There are of course many instances where pathogenic bacteria lose virulence in pa.s.sing from one animal to another, the human smallpox virus, for example, producing typical cowpox in an inoculated heifer. These facts help to explain why certain infections have grown less virulent in the course of history, and why infections of which civilized man has become tolerant prove fatal when imparted to the primitive peoples of Australia.

Pasteur's preventive inoculation for anthrax was tested under dramatic circ.u.mstances at Melun in June, 1881. Sixty sheep and a number of cows were subjected to experiment. None of the sheep that had been given the preventive treatment died from the crucial inoculation; while all those succ.u.mbed which had not received previous treatment. The test for the cows was likewise successful. Pasteur thought that in places where sheep dead of anthrax had been buried, the microbes were brought to the surface in the castings of earthworms. Hence he issued certain directions to prevent the transmission of the disease. He also aided agriculture by discovering a vaccine for swine plague.

When Pasteur at the age of fifteen was in Paris, overcome with homesickness, he had exclaimed, "If I could only get a whiff of the old tannery yard, I feel I should be cured." Certainly every time he came in contact with the industries--silk, wine, beer, wool--his scientific insight, Antaeus-like, seemed to revive. All his life he had preached the doctrine of interchange of service between theory and practice, science and the occupations. What he did is more eloquent than words. His theory of molecular dissymmetry, that the atoms in a molecule may be arranged in left-hand and right-hand spirals or other tridimensional figures corresponding to asymmetrical crystals, touches the abstruse question of the const.i.tution of matter. His preventive treatment breathes new life into the old dictum _similia similibus curantur_. The view he adopted of the gradual transformation of species offers a new interpretation of the speculations of philosophy in reference to being and becoming and the relation of the real to the concrete. Yet Pasteur felt he could learn much of value from the simplest shepherd or vine-dresser.

He was complete in the simplicity of his affections, in his compa.s.sion for all suffering, in the warmth of his religious faith, and in his devotion to his country. He thought France was to regain her place in the world's esteem through scientific progress. He was therefore especially gratified in August, 1881, at the thunders of applause which greeted his appearance at the International Medical Congress in London.

There he was introduced to the Prince of Wales (_fondateur de l'Entente Cordiale_), "to whom I bowed, saying that I was happy to salute a friend of France."

Pasteur's investigation of rabies began in this same year. Difficulty was found in isolating the microbe of the rabic virus, but an inoculation from the medulla oblongata of a mad dog injected into one of the brain membranes (dura mater) of another dog invariably brought on the symptoms of rabies. To obtain attenuation of the virus it was sufficient to dry the medulla taken from an infected rabbit. The weakened virus increased in strength when cultivated in a series of rabbits. Pasteur obtained in inoculations of graded virulence, which could be administered hypodermically, a means of prophylaxis after bites. He conjectured that in vaccinal immunity the virus is accompanied by a substance which makes the nervous tissue unfavorable for the development of the microbe.

It was not till 1885 that he ventured to use his discovery to prevent hydrophobia. On July 6 a little boy, Joseph Meister, from a small place in Alsace was brought by his mother to Paris for treatment. He had been severely bitten by a mad dog. Pasteur, with great trepidation, but moved by his usual compa.s.sion, undertook the case. The inoculations of the attenuated virus began at once. The boy suffered little inconvenience, playing about the laboratory during the ten days the treatment lasted.

Pasteur was racked with fears alternating with hopes, his anxiety growing more intense as the virulence of the inoculations increased. On August 20, however, even he was convinced that the treatment was a complete success. In October a shepherd lad, who, though badly bitten himself, had saved some other children from the attack of a rabid dog, was the second one to benefit by the great discovery. Pasteur's exchange of letters with these boys after they had returned to their homes reveals the kindliness of his disposition. His sentiment toward children had regard both to what they were and to what they might become. One patient, brought to him thirty-seven days after being bitten, he failed to save. By March 1 Pasteur reported that three hundred and fifty cases had been treated with only one death.

When subscriptions were opened for the erection and endowment of the Pasteur Inst.i.tute, a sum of 2,586,680 francs was received in contributions from many different parts of the world. Noteworthy among the contributors were the Emperor of Brazil, the Czar of Russia, the Sultan of Turkey, and the peasants of Alsace. On November 14, 1888, President Carnot opened the inst.i.tution, which was soon to witness the triumphs of Roux, Yersin, Metchnikoff, and other disciples of Pasteur.

In the address prepared for this occasion the veteran scientist wrote:--

"If I might be allowed, M. le President, to conclude by a philosophical remark, inspired by your presence in this home of work, I should say that two contrary laws seem to be wrestling with each other at the present time; the one a law of blood and death, ever devising new means of destruction and forcing nations to be constantly ready for the battlefield--the other, a law of peace, work, and health, ever developing new means of delivering man from the scourges which beset him.

"The one seeks violent conquests, the other the relief of humanity. The latter places one human life above any victory; while the former would sacrifice hundreds and thousands of lives to the ambition of one. The law of which we are the instruments seeks, even in the midst of carnage, to cure the sanguinary ills of the law of war; the treatment inspired by our antiseptic methods may preserve thousands of soldiers. Which of these two laws will ultimately prevail G.o.d alone knows. But we may a.s.sert that French science will have tried, by obeying the law of humanity, to extend the frontiers of life."

REFERENCES

W. W. Ford, _The Life and Work of Robert Koch_, Bulletin of the Johns Hopkins Hospital, Dec. 1911, vol. 22.

C. A. Herter, _The Influence of Pasteur on Medical Science_, Bulletin of the Johns Hopkins Hospital, Dec. 1903, vol. 14.

E. O. Jordan, _General Bacteriology_ (fourth edition, 1915).

Charles C. W. Judd, _The Life and Work of Lister_, Bulletin of the Johns Hopkins Hospital, Oct. 1910, vol. 21.

Stephen Paget, _Pasteur and After Pasteur_.

W. T. Sedgwick, _Principles of Sanitary Science_.

Rene Vallery-Radot, _Life of Pasteur_.

CHAPTER XVII

SCIENCE AND INVENTION--LANGLEY'S AEROPLANE

In his laudation of the nineteenth century Alfred Russel Wallace ventured to enumerate the chief inventions of that period: (1) Railways; (2) steam navigation; (3) electric telegraphs; (4) the telephone; (5) friction matches; (6) gas-lighting; (7) electric-lighting; (8) photography; (9) the phonograph; (10) electric transmission of power; (11) Rontgen rays; (12) spectrum a.n.a.lysis; (13) anaesthetics; (14) antiseptic surgery. All preceding centuries--less glorious than the nineteenth--can claim but seven or eight capital inventions: (1) Alphabetic writing; (2) Arabic numerals; (3) the mariner's compa.s.s; (4) printing; (5) the telescope; (6) the barometer and thermometer; (7) the steam engine. Similarly, to the nineteenth century thirteen important theoretical discoveries are ascribed, to the eighteenth only two, and to the seventeenth five.

Of course the very purpose of these lists--namely, to compare the achievements of one century with those of other centuries--inclines us to view each invention as an isolated phenomenon, disregarding its antecedents and its relation to contemporary inventions. Studied in its development, steam navigation is but an application of one kind of steam engine, and, moreover, must be viewed as a phase in the evolution of navigation since the earliest times. Like considerations would apply to railways, antiseptic surgery, or friction matches. The nineteenth-century inventor of the friction match was certainly no more ingenious (considering the means that chemistry had put at his disposal) than many of the savages who contributed by their intelligence to methods of producing, maintaining, and using fire. In fact, as we approach the consideration of prehistoric times it becomes difficult to distinguish inventions from the slow results of development--in metallurgy, tool-making, building, pottery, war-gear, weaving, cooking, the domestication of animals, the selection and cultivation of plants.

Moreover, it is scarcely in the category of invention that the acquisition of alphabetic writing or the use of Arabic numerals properly belongs.

These and other objections, such as the omission of explosives, firearms, paper, will readily occur to the reader. Nevertheless, these lists, placed side by side with the record of theoretic discoveries, encourage the belief that, more and more, sound theory is productive of useful inventions, and that henceforth it must fall to scientific endeavor rather than to lucky accident to strengthen man's control over Nature. Even as late as the middle of the nineteenth century accident and not science was regarded as the fountain-head of invention, and the view that a knowledge of the causes and secret motions of things would lead to "the enlarging of the bounds of human empire to the effecting of all things possible" was scouted as the idle dream of a doctrinaire.

In the year 1896 three important advances were made in man's mastery of his environment. These are a.s.sociated with the names of Marconi, Becquerel, and Langley. It was in this year that the last-named, long known to the scientific world for his discoveries in solar physics, demonstrated in the judgment of competent witnesses the practicability of mechanical flight. This was the result of nine years'

experimentation. It was followed by several more years of fruitful investigation, leading to that ultimate triumph which it was given to Samuel Pierpont Langley to see only with the eye of faith.

The English language has need of a new word ("plane") to signify the floating of a bird upon the wing with slight, or no, apparent motion of the wings (_planer_, _schweben_). _To hover_ has other connotations, while _to soar_ is properly to fly upward, and not to hang poised upon the air. The miracle of a bird's flight, that steady and almost effortless motion, had interested Langley intensely--as had also the sun's radiation--from the years of his childhood. The phenomenon (the way of an eagle in the air) has always, indeed, fascinated the human imagination and at the same time baffled the comprehension. The skater on smooth ice, the ship riding at sea, or even the fish floating in water, offers only an incomplete a.n.a.logy; for the fish has approximately the same weight as the water it displaces, while a turkey buzzard of two or three pounds' weight will circle by the half-hour on motionless wing upheld only by the thin medium of the air.

In 1887, prior to his removal to Washington as Secretary of the Smithsonian Inst.i.tution, Langley began his experiments in aerodynamics at the old observatory in Allegheny--now a part of the city of Pittsburgh. His chief apparatus was a whirling table, sixty feet in diameter, and with an outside speed of seventy miles an hour. This was at first driven by a gas engine,--ironically named "Automatic,"--for which a steam engine was subst.i.tuted in the following year. By means of the whirling table and a resistance-gauge (dynamometer chronograph) Langley studied the effect of the air on planes of varying lengths and breadths, set at varying angles, and borne horizontally at different velocities. At times he subst.i.tuted stuffed birds for the metal planes, on the action of which under air pressure his scientific deductions were based. In 1891 he published the results of his experiments. These proved--in opposition to the teaching of some very distinguished scientists--that the force required to sustain inclined planes in horizontal locomotion through the air diminishes with increased velocity (at least within the limits of the experiment). Here a marked contrast is shown between aerial locomotion on the one hand, and land and water locomotion on the other; "whereas in land or marine transport increased speed is maintained only by a disproportionate expenditure of power, within the limits of experiment in such _aerial horizontal transport, the higher speeds are more economical of power than the lower ones_."

Again, the experiments demonstrated that the force necessary to maintain at high velocity an apparatus consisting of planes and motors could be produced by means already available. It was found, for example, that one horse-power rightly applied is sufficient to maintain a plane of two hundred pounds in horizontal flight at a rate of about forty-five miles an hour. Langley had in fact furnished experimental proof that the aerial locomotion of bodies many times heavier than air was possible. He reserved for further experimentation the question of aerodromics, the form, ascent, maintenance in horizontal position, and descent of an aerodrome (?e??d????, traversing the air), as he called the prospective flying machine. He believed, however, that the time had come for seriously considering these things, and intelligent physicists, who before the publication of Langley's experiments had regarded all plans of aerial navigation as utopian, soon came to share his belief.

According to Octave Chanute there was in Europe in 1889 utter disagreement and confusion in reference to fundamental questions of aerodynamics. He thought Langley had given firm ground to stand upon concerning air resistances and reactions, and that the beginning of the solution of the problem of aerial navigation would date from the American scientist's experiments in aerodynamics.

Very early in his investigations Langley thought he received through watching the anemometer a clue to the mystery of flight. Observations, begun at Pittsburgh in 1887 and continued at Washington in 1893, convinced him that the course of the wind is "a series of complex and little-known phenomena," and that a wind to which we may a.s.sign a mean velocity of twenty or thirty miles an hour, even disregarding the question of strata and currents, is far from being a mere ma.s.s movement, and consists of pulsations varying both in rate and direction from second to second. If this complexity is revealed by the stationary anemometer--which may register a momentary calm in the midst of a gale--how great a diversity of pressure must exist in a large extent of atmosphere. This _internal work of the wind_ will lift the soaring bird at times to higher levels, from which without special movement of the wings it may descend in the very face of the wind's general course.

From the beginning, however, of his experiments Langley had sought to devise a successful flying machine. In 1887 and the following years he constructed about forty rubber-driven models, all of which were submitted to trial and modification. From these tests he felt that he learned much about the conditions of flight in free air which could not be learned from the more definitely controlled tests with simple planes on the whirling table. His essential object was, of course, to reduce the principles of equilibrium to practice. Besides different forms and sizes he tried various materials of construction, and ultimately various means of propulsion. Before he could test his larger steam-driven models, made for the most part of steel and weighing about one thousand times as much as the air displaced, Langley spent many months contriving and constructing suitable launching apparatus. The solution of the problem of safe descent after flight he in a sense postponed, conducting his experiments from a house-boat on the Potomac, where the model might come down without serious damage.

[Ill.u.s.tration: THE FIRST SUCCESSFUL HEAVIER-THAN-AIR FLYING MACHINE

A photograph taken at the moment of launching Langley's aerodrome May 6, 1896]

It was on May 6, 1896 (the anniversary of which date is now celebrated as Langley Day), that the success was achieved which all who witnessed it considered decisive of the future of mechanical flight. The whole apparatus--steel frame, miniature steam engine, smoke stack, condensed-air chamber, gasoline tank, wooden propellers, wings--weighed about twenty-four pounds. There was developed a steam pressure of about 115 pounds, and the actual power was nearly one horse-power. At a given signal the aeroplane was released from the overhead launching apparatus on the upper deck of the house-boat. It rose steadily to an ultimate height of from seventy to a hundred feet. It circled (owing to the guys of one wing being loose) to the right, completing two circles and beginning a third as it advanced; so that the whole course had the form of a spiral. At the end of one minute and twenty seconds the propellers began to slow down owing to the exhaustion of fuel. The aeroplane descended slowly and gracefully, appearing to settle on the water. It seemed to Alexander Graham Bell that no one could witness this interesting spectacle, of a flying machine in perfect equilibrium, without being convinced that the possibility of aerial flight by mechanical means had been demonstrated. On the very day of the test he wrote to the Academie des Sciences that there had never before been constructed, so far as he knew, a heavier-than-air flying machine, or aerodrome, which could by its own power maintain itself in the air for more than a few seconds.

Langley felt that he had now completed the work in this field which properly belonged to him as a scientist--"the demonstration of the practicability of mechanical flight"--and that the public might look to others for its development and commercial exploitation. Like Franklin and Davy he declined to take out patents, or in any way to make money from scientific discovery; and like Henry, the first Secretary of the Smithsonian Inst.i.tution (to whom the early development of electro-magnetic machines was due), he preferred to be known as a scientist rather than as an inventor.

Nevertheless, Langley's desire to construct a large, man-carrying aeroplane ultimately became irresistible. Just before the outbreak of the Spanish War in 1898 he felt that such a machine might be of service to his country in the event of hostilities that seemed to him imminent.

The attention of President McKinley was called to the matter, and a joint commission of Army and Navy officers was appointed to make investigation of the results of Professor Langley's experiments in aerial navigation. A favorable report having been made by that body, the Board of Ordnance and Fortification recommended a grant of fifty thousand dollars to defray the expenses of further research. Langley was requested to undertake the construction of a machine which might lead to the development of an engine of war, and in December, 1898, he formally agreed to go on with the work.

He hoped at first to obtain from manufacturers a gasoline engine sufficiently light and sufficiently powerful for a man-carrying machine.

After several disappointments, the automobile industry being then in its infancy, he succeeded in constructing a five-cylinder gasoline motor of fifty-two horse-power and weighing only about a hundred and twenty pounds. He also constructed new launching apparatus. After tests with superposed sustaining surfaces, he adhered to the "single-tier plan."

There is interesting evidence that in 1900 Langley renewed his study of the flight of soaring birds, the area of their extended wing surface in relation to weight, and the vertical distance between the center of pressure and the center of gravity in gulls and different species of buzzards. He noted among other things that the tilting of a wing was sufficient to bring about a complete change of direction.

By the summer of 1903 two new machines were ready for field trials, which were undertaken from a large house-boat, especially constructed for the purpose and then moored in the mid-stream of the Potomac about forty miles below Washington. The larger of these two machines weighed seven hundred and five pounds and was designed to carry an engineer to control the motor and direct the flight. The motive power was supplied by the light and powerful gasoline engine already referred to. The smaller aeroplane was a quarter-size model of the larger one. It weighed fifty-eight pounds, had an engine of between two and a half and three horse-power, and a sustaining surface of sixty-six square feet.

This smaller machine was tested August 8, 1903, the same launching apparatus being employed as with the steam-driven models of 1896. In spite of the fact that one of the mechanics failed to withdraw a certain pin at the moment of launching, and that some breakage of the apparatus consequently occurred, the aeroplane made a good start, and fulfilled the main purpose of the test by maintaining a perfect equilibrium. After moving about three hundred and fifty feet in a straight course it wheeled a quarter-circle to the right, at the same time descending slightly, the engine slowing down. Then it began to rise, moving straight ahead again for three or four hundred feet, the propellers picking up their former rate. Once more the engine slackened, but, before the aeroplane reached the water, seemed to regain its normal speed. For a third time the engine slowed down, and, before it recovered, the aeroplane had touched the water. It had traversed a distance of one thousand feet in twenty-seven seconds. One of the workmen confessed that he had poured into the tank too much gasoline.

This had caused an overflow into the intake pipe, which in turn interfered with the action of a valve.

The larger aeroplane with the engineer Manly on board was first tested on October 7 of the same year, but the front guy post caught in the launching car and the machine plunged into the water a few feet from the house-boat. In spite of this discouraging mishap the engineers and others present felt confidence in the aeroplane's power to fly. What would to-day be regarded by an aeronaut as a slight setback seemed at that moment like a tragic failure. The fifty thousand dollars had been exhausted nearly two years previously; Professor Langley had made as full use as seemed to him advisable of the resources put at his disposal by the Smithsonian Inst.i.tution; the young men of the press, for whom the supposed aberration of a great scientist furnished excellent copy, were virulent in their criticisms. Manly made one more heroic attempt under very unfavorable conditions at the close of a winter's day (December 8, 1903). Again difficulty occurred with the launching gear, the rear wings and rudder being wrecked before the aeroplane was clear of the ways.

The experiments were now definitely abandoned, and the inventor was overwhelmed by the sense of failure, and still more by the skepticism with which the public had regarded his endeavors.