Part 7 (1/2)

But the principle has not borne the fruit at first expected There is little doubt that it ht be applied to quite a number of human diseases if a serious atteainst its wide application In the first place, the inoculation thus necessary is really a serious h faultyto experi so powerful for ill as pathogenic bacteria The seriousness of the disease siousness, and the co to undergo vaccination at tireat probability of taking the disease But hother less severe diseases, or diseases which are less likely to be taken We are unwilling to be inoculated against ainst the more severe ones which are unco aniainst lockjahich would probably apply equally well to eneral will never adopt it, since the danger from lockjaw is so small Inoculation must then be reserved for diseases which are so severe and so coreat severity, as toto submit to inoculation as a protection A further objection arises from the fact that the i The cattle inoculated against anthrax retain their protective powers for only a few ht be retained in other cases we can not say, but plainly this fact would effectually prevent thisused except in special cases It is out of the question to think of constant and repeated inoculations against various diseases

As a result, the principle of inoculation as an aid in preventive medicine has not proved of very much value The only other human disease in which it has been attempted seriously is Asiatic cholera This disease in times of epidereat as to justify such inoculation

Several bacteriologists have in the last few years been trying to discover a harainst 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 ainst cholera which is perhaps as efficacious as vaccination is against smallpox Whether it will ever be used to any extent is doubtful, since, as already pointed out, we are in a position to avoid cholera epideuarding the water supply, it is not likely that the method of inoculation will ever be widely used

Another instance of the application of preventive inoculation has been made, but one based upon a different principle Hydrophobia is certainly one of the h comparatively rare Its rarity would effectually prevent ainst it, but its severity would make one who had been exposed to it by the bite of a rabid animal ready to submit to almost any treatment that promised to ward off the disease In the atteainst this disease it was necessary, therefore, to find a method that could be applied after the time of exposure--ie, after the individual had been bitten by the rabid ani period of incubation, and one that has proved long enough for the purpose A ainst 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 froainst anthrax It does not appear to give rise to athe 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 accustoer and larger doses It is by this power, apparently, that the inoculation against hydrophobia produces its effect Material containing the hydrophobia poison (taken from the spinal cord of a rabbit dead with the disease) is injected into the individual after he has been bitten by a rabid animal The poisonous material in the first injection is very weak, but is followed later by a more powerful inoculation The result is that after a short ti the hydrophobia poisons Before the incubation period of the original infectious matter from the bite of the rabid anihly acquired a tolerance of the poison that he successfully resists the attack of the infection This method of inoculation thus neutralizes the effects of the disease by anticipating them

The method of treatment of hydrophobia met with extraordinarily violent opposition For several years it was regarded as astatistics froly on one side as to quiet opposition and bring about a general conviction that the method is a success

The method of preventive inoculation has not been extensively applied to human diseases in addition to those uard against diphtheria

A animals, experiment has shown that such methods can quite easily be obtained, and doubtless the saht practical or feasible to apply them

But, for reasons mentioned, this feature of preventive medicine will always remain rather unimportant, and will be confined to a few of the more violent diseases

It le attack with recovery conveys immunity This question is really a part of the one already discussed as to the method by which the body cures disease We have seen that this is in part due to the development of chemical substances which either neutralize the poisons or act as germicide upon 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 ani bacteria in one case are still present to prevent a second attack of the sa which these forces are active and sufficient to cope with any new invaders deter which the immunity lasts Until, therefore, we can ansith ht about in case of disease, we shall be unable to explain the method of immunity

LIMITS OF PREVENTIVE MEDICINE

With all the advance in preventive medicine we can not hope to avoid disease entirely We are discovering that the sources of disease are on all sides of us, and so omnipresent that to avoid them completely is iuards which bacteriology has taught us should be applied in order to avoid the different diseases, ould surround ourselves with conditions which would h for us to eat no food except when it is hot, to drink no water except when boiled, and to drink no milk except after sterilization; but these would not satisfy the necessary conditions for avoiding disease Towhich has not been sterilized, or should follow the handling by i 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 hope for is to point out the most common and prolific sources of infection, and thus enable civilized man to avoid some of his most common troubles It becomes a question, therefore, where ill best draw the line in the euards Shall we drink none except sterilized milk, and no water unless boiled? or shall we put these occasional sources of danger in the saers which can be avoided by not using the bicycle or riding on the rail, but in regard to which the remedy is too oppressive for application?

Indeed, when viewed in a broad philosophical light it ers Strength in the organism comes from the use rather than the disuse of our powers

It is certain that the general health and vigour ofdangers

Resistance to disease our, and this is to be developed in mankind by the application of the principle of natural selection In accordance with this principle, disease will gradually re those of greater vigour Parasitic bacteria are thus athe continued life of the weaker then mankind By preventive medicine many a weak individual ould otherwise succuer

Whatever be our hu 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 ere to take into consideration sied to recommend a syste to death all weakly individuals, that only the strong enerations In this light, of course, parasitic diseases would be an assistance rather than a detriment to the huain be do men, and our conscience tells us to do all we can to help the weak We shall doubtless do all possible to develop preventive anisms But it is at all events well for us to reth of the hu it, and the power of the huanisuards us from attack Here, as in other directions, the principles of ether with their undoubted favourable influence upon mankind, certain tendencies toeakness While we shall still do our utmost to develop preventive medicine in a proper way, it may be well for us to remember these facts e co where to draw the li infectious diseases

CURATIVE MEDICINE

Bacteriology has hitherto contributed less to curative than to preventive medicine Nevertheless, its contributions to curative medicine have not been unimportant, and there is promise of much more in the future It is, of course, unsafe to make predictions for the future, but the accoive much hope as to further results