Bacteriologist

“ Such a man should have had thorough training in the principles of bacterial manipulation, but it is quite unnecessary that he should be an expert bacteriologist, especially if a competent bacteriologist is retained for consultation in cases of doubt or difficulty. ”

“ The varieties of micro-organisms are multitudinous, doubtless many more in number than the microscopist and the bacteriologist expert have yet isolated and registered as capable of identification. Granted that the majority of these are non-pathogenic to humanity, still a formidable number, including some which are very generally disseminated, are virulently pathogenic, and many are suspect. ”

“ The bacteriologist examines a culture from the throat of the patient and because he finds the germs present he says the germs cause the dis-ease, since no other cause is known; strange to say, however, when the patient is adjusted and the tissues become normal it is not necessary to kill the germs. They will starve to death and Innate will excrete them.
Bacteria are found everywhere and in almost everything. In food, water, on the walls and floors, and in the pores of the skin. All life is due to the action of these bacteria. ”

“ Latterly bacteriologists have come to understand that it is not so much the presence of organisms which is injurious to man and other animals, as it is their products which cause the mischief; and the amount of toxic product bears no known proportion to the degree of invasion by the bacteria. The various and widely differing modes of action in bacteria are therefore dependent upon these three elements: the tissues or medium, the bacteria, and the products of the bacteria; and in all organismal processes these three elements act and react upon each other. ”

“ In practice, bacteriologists do not use the rough and ready methods that we used in dealing with the Hay Bacillus. They prepare pure cultures and cultivate the bacteria on various substances, differing markedly from those on which they originally lived. ”

“ Whilst there can be no doubt as to the advantage of a wider dissemination of the ascertained facts concerning bacteria, it should be borne in mind that only patient, skilled observation and experimental research in well-equipped laboratories can advance this branch of science, or indeed train bacteriologists. The lives of Darwin and of Pasteur adequately illustrate this truth. ”

“ "Well, I'm a bacteriologist, you know. I live in a nine-hundred-diameter microscope. I can hardly claim to take serious notice of anything that I can see with my naked eye. ”

“ Roux and some other eminent bacteriologists suggest that bacteria should be classified according to their method of spore formation.
20
THE INFLUENCE OF EXTERNAL CONDITIONS ON GROWTH OF BACTERIA
Nutritive Medium. In the very earliest days of the study of micro-organisms it was observed that they mostly congregate where there is pabulum for their nourishment. The reason why fluids such as milk, and dead animal matter such as a carcass, and living tissues such as a man's body contain so many microbes is because each of these three media is favourable to their growth. ”

“ Sometimes a bacterium can be readily recognized from one or two characters, but not infrequently a whole series of tests must be made before the species is determined. As our knowledge has advanced it has become abundantly evident that the so-called pathogenic bacteria are not organisms with special features, but that each is a member of a group of organisms possessing closely allied characters. From the point of view of evolution we may suppose that certain races of a group of bacteria have gradually acquired the power of invading the tissues of the body and producing disease. ”

“ The recommendation of sanitarians that water or milk or food suspected of being contaminated by pathogenic bacteria should be exposed to a boiling temperature before it is used is based upon the experimental data referred to; and the knowledge that organic liquids can be sterilized by heat constitutes the foundation upon which the bacteriology of the present day has been established. To obtain reliable information with reference to the biological characters of any particular micro-organism it is necessary to experiment with pure cultures, and this requires a sterile culture medium. ”

“ This application of biology to life and its problems has in recent years been nowhere more marked than in the realm of bacteriology. This comparatively new science, associated with the great names of Pasteur, Koch, and Lister, furnishes indeed a stock illustration of the applicability of pure biology. Turn where we will, we shall find the work of the unseen hosts of bacteria daily claiming more and more attention from practical people. Thus biology, even when clothed in the form of microscopic cells, is coming to occupy a new place in the minds of men. ”

“ The facts themselves by their remarkable variety have not aided classification. Names which a few years ago were applied to individual species, like Bacillus subtilis, or Bacterium termo, or Bacillus coli, are now representative, not of individuals, but of families and groups of species. Again, isolated characteristics of certain microbes, such as motility, power of liquefying gelatine, size, colour, and so forth, which at first sight might appear as likely to form a basis for classification, are found to vary not only between similar germs, but in the same germ. ”

“ Chemists, from Pasteur downwards, have made use repeatedly of special bacteria to perform delicate operations in the laboratory which other methods have either failed to accomplish or have performed in a clumsy and less expeditious manner.
There can be no doubt that, as our knowledge grows from day to day, we shall find more and more how much depends upon the work of individual bacteria, and how much importance attaches to the selection of just those varieties which are of value, and the banishment of those which are detrimental ”

“ Experimental medicine has added constantly to the list of diseases caused by bacterial organisms, and the general public has been educated to an adequate conception of the importance of the germ as the chief agency in the transmission of disease, with corresponding advantage to the efficiency of personal and public hygiene. At the same time knowledge of the benign bacteria and the enormous role they play in the industries and the arts has become much more widely diffused. Bacteriology is being studied in colleges as one of the cultural sciences ”

“ The object of modern bacteriology is not merely to accumulate tested facts of knowledge, nor only to learn the truth respecting the biology and life-history of bacteria. These are most important things from a scientific point of view. But they are also a means to an end; that end is the prevention of preventable diseases and the treatment of any departure from health. In a science not a quarter of a century old much has already been accomplished in this direction. ”

“ To the busy investigator who cannot afford either the time or space in which to maintain a large bacterial family, it is of immense convenience to be able to obtain at a moment's notice a trustworthy culture, say, of typhoid or tuberculosis, or specimens of obscurer origin from air or water for purposes of investigation. These bacterial cultures are all guaranteed pure, free from contamination or admixture with other and alien micro-organisms, and are strictly what they are represented to be. ”

“ We may summarise the vast mass of historical, physiological, and pathological research extending from 1650 to 1898 in three great periods: the period of detection of living, moving cells (Leeuwenhoek and others in the seventeenth century) ; the period of the discovery of their close relationship to fermentation and putrefaction (Spallanzani, Schulze, Schwann, in the eighteenth century) ; and, thirdly, the period of appreciation of the rôle of bacteria in the economy of nature and in the production of disease (Tyndall, Pasteur, Lister, Koch, in the nineteenth) . ”

“ Just as an unidentified disease in an animal may be determined by testing its serum as above described against known kinds of bacteria, so unknown bacteria isolated from an animal, from water, etc., may be identified by testing them against the blood sera of different animals, each of which has been properly inoculated with a different kind of known bacteria. If the unknown organism is agglutinated by the blood of one of the animals in high dilution, and not by the others, evidently the bacterium is the same as that with which the animal has been inoculated, or immunized, as is usually stated. ”

“ Since Pasteur's pioneering work was carried out, a vast number of investigations have been made in all parts of the world by scientists of almost every nationality on the subject of the distribution of bacteria in air, and not only on their distribution, but on their functions or the place they occupy in the economy of nature. With our increased knowledge concerning their distribution has come our ability to differentiate between individuals, and to adequately assess the value and importance of their work from various points of view. ”

“ Yet bacteriology has its limitations. It is well to recognise this, for the new science has in some measure suffered in the past from over-zealous friends. It cannot achieve everything demanded of it, nor can it furnish a cause for every disease. It is a science fuller of hope than proved and tested knowledge. We are as yet only upon the threshold of the matter. As in the neighbouring realm of chemistry, it is to be feared that bacteriology has not been without its alchemy. ”

“ For most purposes the solid media are to be preferred, since bacterial growth appears as a discrete mass and accidental contamination can be readily recognized. Cultures are made by transferring by means of a sterile platinum wire a little of the material containing the bacteria to the medium. The tubes, after being thus inoculated, are kept at suitable temperatures, usually either at 37° C., the temperature of the body, or at about 20° C., a warm summer temperature, until growth appears. For maintaining a constant temperature incubators with regulating apparatus are used. ”

“ Not only does the close resemblance of the Bacteria to unquestionable plants, such as the Oscillatorioe and the lower forms of Fungi, justify this conclusion, but the manufacturing test settles the question at once. It is only needful to add a minute drop of fluid containing Bacteria, to water in which tartrate, phosphate, and sulphate of ammonia are dissolved; and, in a very short space of time, the clear fluid becomes milky by reason of their prodigious multiplication, which, of course, implies the manufacture of living Bacterium-stuff out of these merely saline matters. ”

“ It would be difficult to say where bacterium germs do not exist. In air, in water, in the soil adhering to tiny particles of every kind, in every region of the earth, from the poles to the equator, they are found. In the substance of the tissues—nay, in the cells of almost all plants, and in the interstices of the tissues of many animals—bacteria germs exist. I know not what part of the body of man and the higher animals is entirely destitute of particles which under favorable circumstances develop into bacteria. ”

“ Microscopic methods, although somewhat complicated have been so far developed that some species of bacteria can be as promptly recognized under the microscope as an acquaintance met upon the street.
Bacteriology is now being studied and investigated as a field of research in hundreds of laboratories, and in every university in Europe and America. Bacteriology has added as much to man’s wealth and happiness as any of the applied sciences. ”

“ In this and all other matters connected with bacteriology, such as germs, sero-therapeutics, &c., the medical profession now-a-days receives a good deal of satirical remarks 33 from sceptical lay public. It is natural that it should be so, for the science of bacteriology is still in its infancy, and many of its practical applications are still in their experimental stage. But undoubtedly the science is advancing, and by its aid we are now better able to understand diseases and their nature. Many facts have been demonstrated and proved with precision. ”

“ In this method the bacteria are distributed in a gelatine or agar medium liquefied by heat, and the medium is then poured out on sterile glass plates or in shallow glass dishes, and allowed to solidify. Each bacterium capable of growth gives rise to a colony visible to the naked eye, and if the colonies are sufficiently apart, an inoculation can be made from any one to a tube of culture-medium and a pure culture obtained. ”

“ THE story of bacteriology can best be told by recounting the labors of Pasteur, for while bacteria were known and theories of infection had been elaborated and vaccination practised before his time, it was he who definitely established the importance of bacteria in putrefaction, fermentation and disease, and gave to vaccination a scientific basis. The influence of these labors is compatible in medicine only to that of Virchow in his field and is as great as that exerted in general biology by Darwin's researches. ”

“ Let it be granted that, by means not now explicable, the germs of bacteria, destructible in filtered infusions at a boiling temperature, are feebly, and at times, able to survive a slight continuation of the boiling-point in infusions containing solid particles without apparent injury—is not that a ground for inquiring the reason why, rather than for inferring "spontaneous generation?" If we can prove that in ninety-nine cases out of one hundred actual germs are destroyed at 212° Fahr.,but that, in exceptional circumstances, the remaining one case yields bacteria after exposure to 212° Fahr. ”