Needham, who experimented on the spontaneous generation of "infusion animals," met with general acceptance until Spallanzani (1769), the greatest experimenter of his age, overthrew his claim so completely that Appert (1809) was able to devise a successful method for the preservation of food materials on the basis of their work. This was the first practical result of the older bacteriology. New opponents continued to arise until Franz Schulze (1836), Schwann (1837), Schröder and Von Dusch (1854-1861), Van der Brock (1857), and Pasteur (from 1857 onward), overthrew by. conclusive evidence every argument for spontaneous generation and demonstrated that all microbes arise by legitimate descent out of germs of the same kind. Harvey's law, Omne vivum ex ovo, was therefore fully established. Perty was the first to show that the bacteria belong to the vegetable and not to the animal kingdom. The fundamental work of Ferdinand Cohn gave the idea a further blow.

The principal advance in the first half of the nineteenth century was the demonstration of the fact that the bacteria stood in a certain relation to the most highly organized beings, especially to

Stimulated by the establishment of the fact that fermentation and putrefaction were due to the action of living organisms reproduced from similar pre-existing forms, the study of the causal relation of these micro-organisms to disease was taken up with renewed vigor. Reference has already been made to the opinions and hypotheses of the earlier observers as to the microbic origin of infectious diseases. The first positive grounds, however, for this doctrine, founded upon actual experiment, were the investigations into the cause of certain diseases in insects and plants. Thus Bassi, in 1837, demonstrated that a fatal infectious malady of the silk-worm-muscardine-was due to a parasitic micro-organism. Pasteur later devoted several years' study to an exhaustive investigation into the same subject; and in like manner Tulasse, in 1864, and Kühne, in 1855, showed that certain specific affections in grains and vegetables, e. g. in the potato, were due to the invasion of parasites.

Very soon after this it was demonstrated that micro-organisms were the cause of certain infectious diseases in man and the higher animals.

Bacteriological research has always been of special interest to physicians. Many of the most distinguished physicians of the day, in the earlier history of the science, concerned themselves in

these investigations, and the progress made during the last ten to twenty years has been largely due to their work.

Discovery of Anthrax Bacillus.-Davaine, a famous French physician, has the honor of having first demonstrated the causal relation of a micro-organism to a specific infectious disease in man and animals. The anthrax bacillus was discovered in the blood of animals, dying from this disease, by Pollender, in 1849, and by Davaine in 1850; but it was not until 1863 that the last-named observer demonstrated by inoculation experiments that the bacillus was the cause of anthrax. These experiments were subsequently confirmed by Pasteur, Koch and others.

Koch advanced this line of work in a remarkable degree by the methods he devised about 1880. One of the greatest services that he has rendered to bacteriology, is his invention of methods of pure culture on solid media by means of which such isolated colonies, originating from a single germ, can be cultivated at will and obtained free from any admixture with germs of any other kinds. The isolation of pure cultures of a large number of microparasites was achieved and in many cases it was demonstrated by successful transfer to animals that the microbes had great significance in the origination of those diseases in which they were observed. In this series of investigations, Koch's discovery in 1882 of the germs of tuberculosis stands out conspicuously as especially epochal.

Prior to Koch's discovery, many original investigators were busy in other directions. Obermeier, in 1873, discovered the spirochate of relapsing fever. Von Recklinghausen, Waldeyer, Klebs and Weigert had already found bacteria in the tissues in various diseases when Koch in 1878 published his investigations upon wound infections. According to his conclusions, every special disease had corresponding to it a special disease germ just as there appeared to be a special germ for each fermentation. Pasteur's comprehensive work had built the foundation for the conception that each special fermentation and disease was causally dependent upon a special micro-organism. The brilliant results which Lord Lister obtained, in 1863-1870, in the antiseptic treatment of wounds, to prevent or inhibit the action of infective organisms, exerted a powerful influence on the doctrine of bacterial infections, causing it to be recognized far and wide and gradually lessening the number of its opponents.

Neisser, in 1879, discovered the "gonococcus" in gonorrhoeal discharges. In 1880, Eberth and Koch independently observed

the typhoid bacillus, but it was not until 1884 that Gaffky published his important researches, and proved the etiological relation of this bacillus to typhoid fever.

Sternberg and Pasteur independently observed (1880) a pathogenic micrococcus in saliva, which was subsequently proved by Fränkel and others (1885) to be the organism most commonly associated with acute croupous pneumonia and now recognized as the usual cause of that disease.

The year 1882, made memorable by Koch's discovery of the tubercle bacillus, will also be remembered as the year when Pasteur published his investigations upon "rouget" or hog erysipelas. In this year, also, his first communication upon rabies appeared. In 1882, also, Loeffler and Schütz discovered the bacillus of glanders.

In 1884, Koch discovered the cholera spirillum, and Loeffler the diphtheria bacillus, though it had been observed by Klebs the year before. The tetanus bacillus was also discovered in 1884 by Nicolaier, although it was not until 1889 that it was obtained in pure culture by Kitasato.

In 1892, Pfeiffer and Canon independently discovered a bacillus which is believed to be the specific cause of influenza.

These include some of the most important pathogenic bacteria, the discovery of which is of special interest to us, although under the subject of Etiology we shall refer more particularly to them as well as others.

Like all branches of theoretical and practical medicine, bacteriology owes much of its early advancement to the leaders of the Prussian Army Medical Department. The Prussian surgeon Struck, as head of the Imperial Board of Health in Berlin, took the initiative in creating the first standard working laboratory which served as a model for all subsequent institutions. Without this powerful aid Koch could not have developed his pioneer methods. Earlier pupils of the Army Medical School, like Helmholtz, Virchow, Reichert, Leyden, Fisher, and Nothnagle, had already achieved important professional positions; and upon the establishment of hygienic and bacteriological laboratories and the creation of professorships, German army physicians, and chiefly, indeed, those who were pupils of this institute, appeared as workers of the first rank. Among these we may name Behring, Buchner, Fischer, Gärtner, Gaffky, Loeffler, R. Pfeiffer, and Schrötter.

In order to appreciate the vast difference between the present existing methods of diagnosis and treatment and those which were

in vogue prior to the discovery of the bacteriologists, let us go back to the early part of the century just passed.

In the Fourth Volume of the "Medical Repository" is printed a paper of special interest to us, entitled "The Improvements, Progress and State of Medicine in the Eighteenth Century." This paper was read before the Medical Society of South Carolina on the first day of the nineteenth century. No doubt the writer made as much of his subject as possible, and the list of the discoveries and developments of the hundred years then just passed was as follows: Improvements in anatomy in the preparation of specimens; new operations in surgery; instruction of the deaf; experiments with poison on living animals; establishment of humane societies; cool regimen in fevers and smallpox; establishment of medical societies, hospitals and infirmaries; improvement and simplification of the materia medica; discoveries in chemistry; triumph of physic over smallpox by inoculation and over scurvy by vegetable diet and oxygen; and the abatement of plague and pestilential fevers. At that time these were considered wonderful advances, but appear to us, no doubt, as will a description of the advances made during the nineteenth century to an observer a hundred years hence.

Treatment of Disease in the Early Part of the Nineteenth Century. In the early part of the nineteenth century the recognized methods of treatment were blood-letting, blisters, cathartics, and emetics, without any reference to the diseased condition, and it was heresy to advocate any other methods. People who fell victims to disease died, often because of the heroic measures employed to counteract the maladies which afflicted them. Indeed, many physicians began to feel that more patients would recover if nature were left, unaided, to fight the disease. Few, however, had the temerity to voice these sentiments, and the few that did suffered ostracism because of their expressed views. In England Sir John Forbes incurred the displeasure and contempt of his fellow-practitioners by expressing his belief that no treatment at all was better than the treatment then in vogue. This was the condition of affairs in the early part of the nineteenth century, and it is little wonder that when Hahnemann began to teach his doctrines he soon found many followers.

Domination of Systems of Medicine.-At the beginning of the nineteenth century, the so-called systems dominated the practice of medicine, for every prominent man considered it incumbent upon prominence in their profession to promulgate a complete

personal theory of medicine, to which all facts, if necessary, must be clipped or stretched to fit. Boerhaave considered that disease was due to the laxity or rigidity of the solids and the acidity or alkalinity of the fluids of the body, as the most important of all. Hoffman made diseases dependent upon the motions and moving powers of the animal economy. Rosari was the author of a system by which patients were treated with enormous doses of powerful and poisonous drugs, and cases were related at length of persons with slight illness slowly dying, poisoned by aconite, tartar emetic and digitalis. To this and the unmentionable "system of isopathy," homoeopathy was to some extent a reaction.

Medical Periodicals of 1800.-An examination of the medical periodicals of one hundred years ago is of greater assistance in showing what the physician of that time was interested in, than a similar examination of the more formal medical treatise. The latter was more under the influence of the moribund theories of medicine.

There seemed to be a tendency to the publication of papers describing epidemics in comparatively remote countries, such as the West Indies, numerous articles on chemistry, of varying degrees of absurdity, e. g., a paper proving that water could be entirely converted into air by repeated freezing. Another long paper on observations on the "Influence of the Moon on Climate and the Animal Economy"; with a proper method of treatment of diseases when under the power of that luminary. An abstract of a paper on "Sick Headach" was read before the Hartford County (Conn.) Society in September, 1797 ("Medical Repository," 1798), by Dr. Nathaniel Dwight. His treatment was "half a pint of hard cider drank on an empty stomach in the morning." Some one has wittingly said: "We must conclude that if the 'headach' sees fit to appear after dinner it must wait 'till the next day for treatment.'

Death of Washington.-The illness and death of Washington, occurring so near the close of the eighteenth century, caused by an acute disease, demanding energetic and intelligent treatment, as well as the great prominence of the patient, naturally attracts attention, as the management of his case affords an example of the most approved treatment of that day, and shows, in one instance, the great benefit derived from bacteriological researches to-day. From the popular record of his illness in Irving's Life, it would appear that he died from laryngeal diphtheria after an