The Story of Germ Life

istory of the world has been almost purely empirical, with a very little of scientific basis. Great hopes are now entertained that these new facts will place this matter upon a more st

y in the line of preventive medicine, although to a certain extent also along the line of curative medicine. This chapter will b

TIVE M

heir cause, but also how infection is brought about, and consequently how contagion may be avoided. Some of the results which have grown up so slowly as to be hardly appreciated are really great triumphs. For instance, the study of bacteriology first led us to suspect, and then demonstrated, that tuberculosis is a contagious disease, and from the time that this was thus proved there has been a slow, but, it is hoped, a sure decline in this disease. Bacteriological study has shown that the source of cholera infection in cases of raging epidemics is, in large part at least, our drinking water; and since this has been known, although cholera has twice invaded

t to nurse; it has told us what diseases are contagious, and in what way; it has told us what sources of contagion should be suspected and guarded against, and has thus done very much to prevent the spread of disease. Its value is seen in the fact that there has been a consta

w several factors, all connected with the metho

teria are in all these cases eliminated from the patient in some way, either from the alimentary canal or from skin secretions or otherwise, and that any nurse with common sense can have no difficulty in determining in what way the infectious material is eliminated from her patients. When this fact is known and take

butor. Food may become contaminated by infectious material in many ways; for example, by contact with sewage, or with polluted water, or even with eating utensils which have been used by patients. Water is also likely to be contaminated with infectious material, and is a fertile source for distributing typhoid and cholera. Milk may become contaminated in a variety of ways, and be a source of distributing the bacteria which produce typhoid fever, tuberculosis, diphtheria, scarlet fever, and a few other less common diseases. Again, infected clothing, bedding

; that tuberculosis may find entrance through the nose in breathing, while types of blood poisoning enter only through wounds or broken skin, we learn at once fundamental facts as to the proper methods of meeting these dangers. We learn that with some diseases care exercised to prevent the swallowing o

wait for a chance of infection, by discovering disinfectants and telling us especially where and when to use them. It has already taught us how to crush out certain forms of epidemics by the proper means of destroying bacteria, and is lessening the dangers from contagious diseases. In short, the study of bacteriology has brough

IA IN

ications known as surgical fever, inflammation, blood poisoning, gangrene, etc., which frequently resulted fatally. These secondary complications were commonly much more serious than the shock of the operation, and it used to be the common occurrence for the patient to recover entirely from the shock, but yield to the fevers which followed. They appeared to be entirely unavoidable, and were indeed regarded as necessary parts of the healing of the wound. Too frequently it appeared that the greater the care taken with the patient

n was an obvious one. At first, however, and for quite a number of years, it was impossible to demonstrate the theory by finding the distinct species of micro- organisms which produced the troubles. We have already seen that there are several different species of bacteria which are associated with this general class of diseases, but that no

st among which is a knowledge of the common sources from which the infection of wounds occurs. At first it was thought that the air was the great source of infection, but the air bacteria have been found to be usually harmless. It has appeared that the more common sources are the surgeon's instruments, or his hands, or the clothing or sponges which are allowed to come in contact with the wounds. It has also appeared that the bacteria which produce this class of troubles are common species, existing everywhere and universally present around the body, clinging to t

sort follow simple surgical wounds it is a testimony to his carelessness. The skilful surgeon has learned that with the precautions which he is able to take to-day he has to fear only the direct effect of the shock of the wound and its subsequent direct influence; but secondary surgical fevers, blood poisoning, and surgical gangrene need not be taken int

hat it was resorted to only on the last extremity; while to-day such operations are hardly regarded as serious. Even brain surgery is becoming more and more common. Possibly our surgeons are passing too far to the other extreme, and, feeling their power of performing so many operations without inconvenience or dange

at the knowledge of curative methods be confined largely to the medical profession, it is eminently desirable that a knowledge of all the facts bearing upon preventive medicine should be distributed as widely as possible. One person can not satisfactorily apply his knowledge of preventive medicine, if his neighbour is ignorant of or careless of the facts.

ON IN IN

others in which the immunity is very great and very lasting, as in the case of scarlet fever. Moreover, the immunity differs with individuals. While some persons appear to acquire a lasting immunity by recovery from a single attack, others will yield to a second attack very readily. But in spite of this the fact of such acquired immunity is beyond question. Apparently all infectious diseases from which a real recovery takes place are followed by a certain amount of protection from a secon

his fact mothers have not infrequently intentionally exposed their children to certain diseases at seasons when they are mild, in order to have the disease "over with" and their children protected in the future. Even the more severe diseases have at times been thus voluntarily a

on anthrax among animals, he learned that here, as in other diseases, recovery, when it occurred, conveyed immunity. This led him to ask if it were not possible to devise a method of giving to animals a mild form of the disease and thus protect them from the more severe type. The problem of giving a mild type of this extraordinarily severe disease was not an easy one. It could not be done, of course, by inoculating the animals with a small number of the bacteria, for their power of multiplication would soon make them indefinitely numerous. It was necessary in some way to diminish their violence. Pasteur succeeded in doing this by causing them to grow in culture fluids for a time at a high temperature. This t

s willing to undergo vaccination at times of epidemics to avoid the somewhat great probability of taking the disease. But mankind is unwilling to undergo such an operation, even though mild, for the purpose of avoiding other less severe diseases, or diseases which are less likely to be taken. We are unwilling to be inoculated against mild diseases, or against the more severe ones which are uncommon. For instance, a method has been devised for rendering animals immune against lockjaw, which would probably apply equally well to man. But mankind in general will never adopt it, since the danger from lockjaw is so small. Inoculation must then be reserved for dis

s have in the last few years been trying to discover a harmless method of inoculating against this disease. Apparently they have succeeded, for experiments in India, the home of the cholera, have been as successful as could be anticipated. Bacteriological science has now in its possession a means of inoculation against cholera which is perh

on, and one that has proved long enough for the purpose. A method of inoculation against this disease has been devised by Pasteur, which can be applied after the individual has been bitten by the rabid animal. Apparently, however, this preventive inoculation is dependent upon a different principle from vaccination or inoculation against anthrax. It does not appear to give rise to a mild form of the disease, thus protecting the individual, but rather to an acquired tolerance of the chemical poisons produced by the disease. It is a well-known physiological fact that the body can become accustomed to tolerate poisons if inured to them by successively larger and larger doses. It is by this power, apparently, that the inoculation against hydrophobia produc

egarded as a mistake. But the constantly accumulating statistics from the Pasteur Institute have been so overw

t diphtheria. Among animals, experiment has shown that such methods can quite easily be obtained, and doubtless the same would be true of mankind if it was thought practical or feas

on the bacteria, or both, and perhaps due in part to an active destruction of bacteria by cellular activity (phagocytosis). There is little reason to doubt that it is the same set of activities which renders the animal immune. The forces which drive off the invading bacteria in one case are still present to prevent a second attack of the sam

PREVENTIVE

no milk except after sterilization; but these would not satisfy the necessary conditions for avoiding disease. To meet all dangers, we should handle nothing which has not been sterilized, or should follow the handling by immediately sterilizing the hands; we should wear only disinfected clothes, we should never put our fingers in our mouths or touch our food with them; we should cease to ride in public conveyances, and, indeed, should cease to breathe common air. Absolute prevention of the chance of infection is impossible. The most that preventive medicine can ho

the struggle is enabled to live a few years longer. Whatever be our humanitarian feeling for the individual, we can not fail to admit that this survival of the weak is of no benefit to the race so far as the development of physical nature is concerned. Indeed, if we were to take into consideration simply the physical nature of man we should be obliged to recommend a system such as the ancient Spartans developed, of exposing to death all weakly individuals, that only the strong might live to become the fathers of future generations. In this light, of course, parasitic diseases would be an assistance rather than a detriment to the human race. Of course such principles will never again be dominant among men, and our conscience tells us to do all we can to help the weak. We shall doubtless do all possible to develop pr

VE MED

curative medicine have not been unimportant, and there is promise of much more in the future. It is, of course, unsafe

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ich proves fatal to the specific germs while growing in the culture media of the laboratory, but commonly these are of little or no use when applied as medicines. In the first place, such substances are usually very deadly poisons. Corrosive sublimate is a substance which destroys all pathogenic germs with great rapidity, but it is a deadly poison, and can not be used as a drug in sufficient quantity to destroy the parasitic bacteria in the body without at the same time producing poisonous effects on the bo

spleen, etc. Even if it were possible to find some drug which would have a very specific effect upon the tuberculosis bacillus, it is plain that it would be a very questionable method of procedure to introduce this into the whole system simply that it might have an effect upon a very small isolated gland. Sometimes such a bacterial affection may be localized in places where it can be specially treated

es are not, however, produced by bacteria but by a microscopic organism of a very different nature, thought to be an animal rather than a plant. Besides this there has been little or no success in discovering specifics in the form of drugs which can be given as medici

ICATRIX

hese hostile conditions are produced perhaps in part by the secretions from the bacteria, for bacteria are unable to flourish in a medium containing much of their own secretions. The secretions which they produce are poisons to them as well as to the individual in which they grow, and after these have become quite abundant the further growth of the bacterium is checked and finally stopped. Partly, also, must we conclude that these hostile conditions are produced by active vital powers in the body of the individual attacked. The individual, as we have seen, in some cases develops a quantity of some substance which neutralizes the bacterial poisons and thus preve

bacteria. In the case of some diseases the poisons are so violent that this practically always occurs, recovery being very exceptional. The poison produced by the tetanus bacillus is of this nature, and recovery from lockjaw is of the rarest occurrence. But in many other diseases the body is able to withstand the poison, and later to recover its resisting powers sufficiently to d

ysician's aim to enable the body to resist the poisons as well as possible and to stimulate it to re-enforce its resistant forces. Drugs have a place in medicine, of course, but this place is chiefly to stimulate the body to react against its invading hosts. They are, as a rule, not specific against definite diseases. We can not hope for much in the way of discovering special medicines adapted to special diseases. We must simply look upon them as means which the physician has in hand for stimulating the natural forc

laced by smaller doses designed to stimulate the lagging body powers. The modern physician makes no attempt to cure typhoid fever, having long since learned his inability to do this, at least if the fever once gets a foothold; but he turns his attention to every conceivable means of increasing the body's strength to resist the typhoid poison, conf

TOXI

o long as this antitoxine is not present the poisons produced by the disease will have their full effect to weaken the body and prevent the revival of its resisting powers to drive off the bacteria. Plainly, if it is possible to obtain this antitoxine in quantity and then inoculate it into the body when the toxic poisons are present, we have a means for decidedly assist

heria bacillus. This poison is easily obtained by causing the diphtheria bacillus to grow in common media in the laboratory for a while, and the toxines develop in quantity; then, by proper filtration, the bacteria themselves can be removed, leaving a pure solution of the toxic poison. Small quantities of this poison are inoculated into the horse at successive intervals. The effect on the horse is the same as if the animal had the disease. Its cells react and produce a considerable quantity of the antitoxine which remains in solution in the blood of the animal. This is not theory, but demonstrated fact. The blood of a horse so treated is found to have the effect of neutralizing the diphtheria p

develop a substance which neutralizes the snake poison. Other diseases are being studied to-day with the hope of similar results. How much further the principle will go we can not say, nor can we be very confident that the same principle will apply very widely. The parasitic diseases are so different in nature that we can hardly expect that a method which is satisfactory in meeting one of the diseases will be very likely to be adapted to another. Vaccination has proved of value in smallpox, but is not of use in other human diseases. Inoc

teracting the poison by his own powers. His cellular activities have, in other words, been for a moment at least turned in the direction of production of antitoxines. It is to be expected, therefore, that after the recovery they will still have this power, and so long as they possess it the individual will have protection from a second attack. When, however, the recovery results from the artificial inoculation of antitoxine the body cells have not actively produced antitoxine. The n

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vast host of living beings thus constitutes a force or series of forces of tremendous significance. Most of the vast multitude we must regard as our friends. Upon them the farmer is dependent for the fertility of his soil and the possibility of continued life in his crops. Upon them the dairyman is dependent for his flavours. Upon them important fermentative industries are dependent, and their universal powers come into action upon a commercial scale in many a place where we have little thought of them in past years. We must look upon them as agents ever at work, by means of which the surface of Nature is enabled to remain fresh and green. Their power is fundamental, and their activities are necessary for the continuance of life. A small number of the vast host, a score or two of species