Part 14
The century opened auspiciously, and those who were awake saw signs of the dawn. The spirit of Science was brooding on the waters. In England the influence of John Hunter stimulated the younger men to the study of the problems of anatomy and pathology. On the Continent the great Boorhaave—the Batavian Hippocrates—had taught correct ways in the study of the clinical aspects of disease, and the work of Haller had given a great impetus to physiology. The researches of Morgagni had, as Virchow had remarked, introduced anatomical thinking into medicine. But theories still controlled practice. Under the teaching of Cullen, the old idea that humors were the seat of disease had given place to a neuro-pathology which recognized the paramount influence of the nervous system in disease. His colleague at Edinburgh, Brown, brought forward the attractive theory that all diseases could be divided into two groups, the one caused by excess of excitement—the sthenic—the other by a deficiency—the asthenic—each having its appropriate treatment, the one by depletion, the other by stimulation. In a certain measure Hahnemann’s theory of homœopathy was a reaction against the prevalent theories of the day, and has survived through the century, though in a much modified form. Some of his views were as follows:
“The only vocation of the physician is to heal; theoretical knowledge is of no use. In a case of sickness he should only know what is curable and the remedies. Of the diseases he cannot know anything except the symptoms. There are internal changes, but it is impossible to learn what they are; symptoms alone are accessible; with their removal by remedies the disease is removed. Their effects can be studied in the healthy only. They act on the sick by causing a disease similar to that which is to be combated, and which dissolves itself into this similar affection. The full doses required to cause symptoms in the well are too large to be employed as remedies for the sick. The healing power of a drug grows in an inverse proportion to its substance. He says, literally: ‘Only potencies are homœopathic medicines.’ ‘I recognize nobody as my follower but him who gives medicine in so small doses as to preclude the perception of anything medicinal in them by means either of the senses or of chemistry.’ ‘The pellets may be held near the young infant when asleep.’ ‘Gliding the hand over the patient will cure him, provided the manipulation is done with firm intention to render as much good with it as possible, for its power is in the benevolent will of the manipulator.’ Such is the homœopathy of Hahnemann, which is no longer recognized in what they call homœopathy to-day.”—(A. JACOBI.)
The awakening came in France. In 1801 Bichat, a young man, published a work on general anatomy, in which he placed the seat of disease, not in the organs, but in the tissues or fabrics of which they were composed, which gave an extraordinary impetus to the investigation of pathological changes. Meanwhile, the study of the appearances of organs and bodies when diseased (morbid anatomy), which had been prosecuted with vigor by Morgagni in the eighteenth century, had been carried on actively in Great Britain and on the Continent, and the work of Broussais stimulated a more accurate investigation of local disorders. The discovery by Laennec of the art of auscultation, by which, through changes in the normal sounds within the chest, various diseases of the heart and lungs could be recognized, gave an immense impetus to clinical research. The art of percussion, discovered by Avenbrugger in the eighteenth century, and reintroduced by Corvisart, contributed not a little to the same. Laennec’s contributions to the study of diseases of the lungs, of the heart, and of the abdominal organs really laid the foundation of modern clinical medicine. A little later Bright published his researches on diseases of the kidneys, from which we date our knowledge of this important subject. One of the most complicated problems of the first half of the century related to the differentiation of the fevers. The eruptive fevers, measles, scarlet fever, and small-pox, were easily recognized, and the great group of malarial fevers was well known; but there remained the large class of continued fevers, which had been a source of worry and dispute for many generations. Louis clearly differentiated typhoid fever, and by the work of his American pupils, W. W. Gerhard and Alfred Stillé, of Philadelphia, and George B. Shattuck, of Boston, typhus and typhoid fevers were defined as separate and independent affections. Relapsing fever, yellow fever, dengue, etc., were also distinguished. The work of Graves and Stokes, of Dublin, of Jenner and Budd, in England, of Drake, Dickson, and Flint, in America, supplemented the labors of the French physicians, and by the year 1860 the profession had reached a sure and safe position on the question of the clinical aspects of fevers.
The most distinguishing feature of the scientific medicine of the century has been the phenomenal results which have followed _experimental investigations_. While this method of research is not new, since it was introduced by Galen, perfected by Harvey, and carried on by Hunter, it was not until well into the middle of the century that, by the growth of research laboratories, the method exercised a deep influence on progress. The lines of experimental research have sought to determine the functions of the organs in health, the conditions under which perversion of these functions occur in diseases, and the possibility of exercising protective and curative influences on the processes of disease.
The researches of the physiological laboratories have enlarged in every direction our knowledge of the great functions of life—digestion, assimilation, circulation, respiration, and excretion. Perhaps in no department have the results been more surprising than in the growth of our knowledge of the functions of the brain and nerves. Not only has experimental science given us clear and accurate data upon the localization of certain functions of the brain and of the paths of sensatory and of motor impulses, but it has opened an entirely new field in the diagnosis and treatment of the diseases of these organs, in certain directions of a most practical nature, enabling us to resort to measures of relief undreamed of even thirty years ago.
The study of physiology and pathology within the past half-century has done more to emancipate medicine from routine and the thraldom of authority than all the work of all the physicians from the days of Hippocrates to Jenner, and we are as yet but on the threshold.
THE GROWTH OF SPECIALISM
The restriction of the energies of trained students to narrow fields in science, while not without its faults, has been the most important single factor in the remarkable expansion of our knowledge. Against the disadvantages in a loss of breadth and harmony there is the compensatory benefit of a greater accuracy in the application of knowledge in specialism, as is well illustrated in the cultivation of special branches of practice. Diseases of the skin, of the eye, of the ear, of the throat, of the teeth, diseases of women and of children, are now studied and practised by men who devote all their time to one limited field of work. While not without minor evils, this custom has yielded some of the great triumphs of the profession. Dentistry, ophthalmology, and gynæcology are branches which have been brought to a state of comparative perfection, and very largely by the labors of American physicians. In the last-named branch the blessings which have been brought to suffering women are incalculable, not only as regards the minor ailments of life, but in the graver and more critical accidents to which the sex is liable.
One of the most remarkable and beneficial reforms of the century has been in the attitude of the profession and the public to the subject of insanity, and the gradual formation of a body of men in the profession who labor to find out the cause and means of relief of this most distressing of all human maladies. The reform movement inaugurated by Tuke in England, by Rush in the United States, by Pinel and Esquirol in France, and by Jacobi and Hasse in Germany, has spread to all civilized countries, and has led not only to an amelioration and improvement in the care of the insane, but to a scientific study of the subject which has already been productive of much good. In this country, while the treatment of the insane is careful and humanitarian, the unfortunate affiliation of insanity with politics is still in many States a serious hinderance to progress.
It may be interesting to take a glance at the state of medicine in this country at the opening of the nineteenth century. There were only three schools of medicine, the most important of which were the University of Pennsylvania and the Harvard. There were only two general hospitals. The medical education was chiefly in the hands of the practitioners, who took students as apprentices for a certain number of years. The well-to-do students and those wishing a better class of education went to Edinburgh or London. There were only two or three medical journals, and very few books had been published in the country, and the profession was dependent entirely upon translations from the French and upon English works. The only medical libraries were in connection with the Pennsylvania Hospital and the New York Hospital. The leading practitioners in the early years were Rush and Physick, in Philadelphia; Hossack and Mitchill, in New York; and James Jackson and John Collins Warren, in Boston. There were throughout the country, in smaller places, men of great capabilities and energy, such as Nathan Smith, the founder of the Medical Schools of Dartmouth and of Yale, and Daniel Drake in Cincinnati. After 1830 a remarkable change took place in the profession, owing to the leaven of French science brought back from Paris by American students. Between 1840 and 1870 there was a great increase in the number of medical schools, but the general standard of education was low—lower, indeed, than had ever before been reached in the medical profession. The private schools multiplied rapidly, diplomas were given on short two-year sessions, and nothing contributed more to the degeneration of the profession than this competition and rivalry between ill-equipped medical schools. The reformation, which started at Harvard shortly after 1870, spread over the entire country, and the rapid evolution of the medical school has been one of the most striking phenomena in the history of medicine in the century. University authorities began to appreciate the fact that medicine was a great department of knowledge, to be cultivated as a science and promoted as an art. Wealthy men felt that in no better way could they contribute to the progress of the race than by the establishment of laboratories for the study of disease and hospitals for the care of the sick poor. The benefactions of Johns Hopkins, of Sims, of Vanderbilt, of Pierpont Morgan, of Strathcona, of Mount-Stephen, of Payne, and of Levi C. Lane and others have placed scientific medicine on a firm basis.
THE GROWTH OF PREVENTIVE MEDICINE
Sanitary science, hygiene, or preventive medicine may claim to be one of the brightest spots in the history of the nineteenth century. Public hygiene was cultivated among the Egyptians, and in the Mosaic law it reached a remarkable organization. The personal hygiene of the Greeks was embraced in the saying, “The fair mind in the fair body,” and the value of exercise and training was fully recognized. The Romans, too, in public and private hygiene, were our superiors in the matter of water supply and baths. But modern sanitary science has a much wider scope and is concerned with the causes of disease quite as much as with the conditions under which these diseases prevail. The foundations of the science were laid in the last century with Jenner’s discovery of vaccination. Howard, too, had grasped the association of fever with overcrowding in the jails, while the possibility of the prevention of scurvy had been shown by Captain Cook and by Sir Gilbert Blaine.
Preventive medicine was a blundering, incomplete science until bacteriology opened unheard-of possibilities for the prevention of disease. Before discussing some of the victories of preventive medicine it will be well to take a brief survey of the growth of the following subject:
SCIENCE OF BACTERIOLOGY
From the brilliant overthrow by Pasteur, in 1861, and by Koch and Cohn, in 1876, of the theory of spontaneous generation, we may date its modern growth. Wrapped up in this theory of spontaneous generation, upon which speculation raged centuries before the invention of the microscope, lies the history of bacteriology.
The ancient Greek and Roman philosophers wrestled with the question, and very interesting views of the relation of germ life to disease are preserved to us in their manuscripts. With the invention of the microscope we can mark the first positive step towards the goal of to-day. A Jesuit priest, Kircher, in 1671, was the first to investigate putrefying meat, milk, and cheese with the crude microscope of his day, and left us indefinite remarks concerning “very minute living worms” found therein. Four years after Kircher a Dutch linen merchant, Antonius von Leeuwenhoek, by improving the lenses of the microscope, saw in rain-water, putrefying fluids, intestinal contents, and saliva, minute, moving, living particles, which he called “animalculæ.” In medical circles of his day these observations aroused the keenest interest, and the theory that these “animalculæ” might be the cause of all disease was eagerly discussed. Pleincz, of Vienna, after much observation of various fluids, putrefying and otherwise, wrote in 1762 that it was his firm belief that the phenomena of diseases and the decomposition of animal fluids were wholly caused by these minute living things.
Notwithstanding such assertions, from his day on until Pasteur, Koch, and Cohn finally proved its misconceptions in 1876, the theory of spontaneous generation held the upper hand in all discussions upon the question.
The stimulus to research as to the causes of disease along the line of bacterial origin did not entirely cease to be felt, and the names of Pollender and Davaine are linked together in the first undoubted discovery of micro-organisms in disease, when the cause of anthrax, a disease of cattle, was solved in 1863. Following closely upon Davaine’s researches, the primary causes of wound infection were worked out, and to the efforts of the British surgeon Lister are due the great advances of modern surgery.
In rapid succession the presence of bacteria was clearly demonstrated in relapsing fever, leprosy, and typhoid fever; but far eclipsing all former discoveries, on account of the magnitude of the difficulties encountered and overcome, were the brilliant demonstrations of the cause of consumption and allied diseases, and that of Asiatic cholera, by Dr. Robert Koch in 1882 and in 1884 respectively.
From that time onward innumerable workers have satisfied the critical scientific world as to the causes of pneumonia, diphtheria, tetanus, influenza, and bubonic plague, besides many diseases of cattle, horses, sheep, and other animals and insects.
Having glanced hastily at the history of bacteriology, we may next consider some facts concerning the germs themselves. What are they? To the lay mind the words germ, microbe, bacterium, and bacillus often convey confused ideas of invisible, wriggling, worm-like creatures, enemies of mankind, ever on the watch to gain a stealthy entrance into our bodies, where they wreak harm and death. Scientifically considered, however, they are the smallest of living things yet known. They are not animals, but are members of the vegetable kingdom, and are possessed of definite yet varying shapes. They consist of a jelly-like substance called protoplasm, which is covered in and held in place by a well-formed membrane of a relatively hard and dense character, exactly similar in composition to the woody fibre of trees.
According to their shape the bacteria are divided into three chief groups, called respectively cocci, bacilli, and spirilla. The cocci are spherical bodies and may exist singly or in pairs, in fours, in clusters, or in chains. In this group we find the smallest bacteria known, many of them not over 1-150,000 of an inch in diameter. The bacilli are rod-like bodies, varying much in size in different species and in members of the same species. They are larger than the cocci, measuring in length from 1-25,000 of an inch to 1-4000, and in breadth from 1-125,000 to 1-16,000 of an inch. Many varieties are possessed of organs of locomotion called flagella.
The spirilla resemble the bacilli, except that they are twisted into corkscrew shapes, or have gently undulating outlines. Upon an average they are much longer than the bacilli, one species being very long, measuring about 1-600 of an inch. As seen in the natural state bacteria are found to be colorless, but it is by the application of various aniline dyes that they are usually studied. These minute plants increase by a simple method of division into two equal parts, or by a more complex process of forming a seed—the so-called spore—which later on develops into the adult form. Under favorable conditions they are able to multiply at an enormous rate; for instance, it has been calculated that a bacillus dividing once every hour would at the end of twenty-four hours have increased to seventeen millions; and if the division continued at the same rate we should find at the end of the third day an incalculable number of billions, whose weight would be nearly seven thousand five hundred tons!
But, fortunately for our welfare, nature by various means renders the possibility of such a happening entirely beyond the slightest chance of realization, her greatest barrier being the lack of an adequate food supply.
The distribution in nature of bacteria is wellnigh universal, occurring as they do in the air we breathe, the water and milk we drink, upon the exposed surfaces of man and animals, and in their intestinal tracts, and in the soil to a depth of about nine feet. But it has been noted that at very high altitudes and in glacier ice none exist, while in the Arctic regions and at sea far from land their numbers are very few.
The conditions governing their growth involve many complex problems, but a few of the chief factors concerned are moisture, air, food, temperature, and light. All bacteria must have moisture, else they die sooner or later, depending upon the hardness of the species, and none can multiply without it. A supply of air is by no means essential to all germs. To some it is absolutely necessary, and such germs are called aerobes. To others air is wholly detrimental, and they constitute the anaerobes, while to the majority of bacteria air supply is a matter of indifference, and in consequence they are grouped under the term facultative anaerobes.
The food supply of many consists of dead animal and vegetable materials, a few require living tissues, while a small number can exist wholly upon mineral salts, or even the nitrogen of the air. The lowest temperature at which some bacteria can multiply is the freezing-point of water, and the highest 170 degrees Fahrenheit. However, the average range of temperature suitable to the majority lies between 60 and 104 degrees Fahrenheit, 98 2-5 degrees Fahrenheit being the most suitable for the growth of disease-producing germs. Light, ordinarily diffused daylight, or its absence, is a matter of no moment to most germs, whereas direct sunlight is a destroyer of all bacteria.
The study of the life histories of these diminutive plants excites the wonder of those who make observations upon them. It is truly marvellous to know that these bacteria can accomplish in their short lives of possibly a few hours or days feats which would baffle the cleverest of chemists if given years of a lifetime to work upon. They give to the farmer the good quality of his crops, to the dairyman superior butter and cheese; they assist in large measure in freeing our rivers and lakes from harmful pollutions. Here it should be strongly emphasized that those bacteria which cause disease are only of a few species, all others contributing to our welfare in countless ways.
Quite as astonishing is the discovery that within the root-knobs of pease and beans live bacteria which by splitting up mineral salts containing nitrogen, and by absorbing nitrogen from the air, give it over to the plant so that it is enabled to grow luxuriantly, whereas, without their presence, the tiller of the soil might fertilize the ground in vain. It is quite possible that not alone pease and beans, but all grasses and plants and trees depend upon the presence of such germs for their very existence, which in turn supply man and animals with their means of existence. Hence we see that these nitrifying bacteria, as they are called, if swept out of existence, would be the cause of cessation of all life upon the globe. And arguing backward, one prominent authority states it as his belief that the first of all life on this earth were those lowly forms of plants which only required the nitrogen of air or salts to enable them to multiply.
Limiting observation now to the sphere of medicine, it will be readily perceived that the presence of bacterial life in a causative relation to disease is an object of paramount regard. The following paragraphs will briefly treat of the diseases associated with micro-organisms and the common modes of infection in each, the chain of events subsequent to an infection, and the possibilities of protection or cure by means of substances elaborated in the body of an individual or animal recently recovered from an infectious disease:
_Anthrax._—A disease chiefly of cattle and sheep, occasionally of man, is caused by the _Bacillus anthracis_, discovered in 1849–50 by Pollender and Davaine. It enters the body through abrasions of the skin, by inhalation of the spores, or seeds, into the lungs, or by swallowing infected material.
_Leprosy._—This disease is caused by a bacillus known as _Bacillus leprae_, which was discovered by Hansen in 1879. It is doubtful if it has been grown outside the body. It is supposed to enter by abrasions of the skin, but it is very feebly contagious, notwithstanding popular ideas as to its supposedly highly contagious nature.
_Tuberculosis._—All forms of this disease, among which is ordinary consumption, are caused by a bacillus closely resembling that of leprosy. It was discovered by Koch in 1880–82, and named _Bacillus tuberculosis_. The ways of infection are by inhaling the dried sputum of consumptives, drinking infected cow’s milk, or eating infected meat.
_Typhoid Fever._—A disease of human beings only. Eberth in 1880 discovered the germ causing it and called it _Bacillus typhosus_. It gains entrance to our bodies chiefly in the milk and water we drink, which comes from infected sources; a rarer method is by inhalation of infected air.
_Diphtheria._—A disease of human beings chiefly. It is caused by a bacillus which was described in 1883–84 by Klebs and Loeffler, and is known as _Bacillus diphtheriae_, or Klebs-Loeffler bacillus. Its mode of entry is by inhaling infected air, or by drinking or eating infected milk or food.
_Cholera._—This disease is peculiar to human beings. Its native home is on the banks of the river Ganges in India, where Koch in 1884 was able to isolate its causative spirillum. Man is infected by drinking contaminated water or by contact.