Epidemics Examined and Explained: or Living Germs Proved by a.n.a.logy to be a Source of Disease.

by John Grove.

PREFACE.

The following pages have been written with a view to render some aid in establishing a sound and firm basis for future research, on that absorbing topic, the Causes and Nature of Epidemic Diseases.

The amount of information already published on Fevers, on the Exanthemata, and on the Plague, is truly astonishing, and the more so when it is considered, that at present no rational account or explanation is given of the causes of these affections.

It appears to me but reasonable to suppose that as every thing on this earth has been created on a wise and unerring principle, Epidemic and Infectious Diseases are only indicative of some serious errors in our social arrangements and habits. The dangers and misery brought upon us by disease, may, as shewn by Dr. Spurzheim and Mr. Combe, be warnings against the infringement of the natural laws.

Indeed, what is more rational than to suppose that the Seeds of Disease are coeval with the fall of man. His first disobedience {vi} brought death:--that his subsequent errors should hasten its approaches is not to be marvelled at. The undetected murderer, though he may escape the punishment human justice would inflict upon him for his delinquency, suffers a penalty in the tortures of conscience, infinitely more horrifying than the most ignominious death. The law of nature is triumphant.

No less certain, though after a different manner, are the consequences of minor forms of disobedience. It is so ordained, that certain diseases shall arise, under peculiar conditions, which may have been brought about by a train of causes, easily imagined, and difficult to be explained, but all having their origin in the vices and errors of man in his moral and social relations.

If man neglects the cultivation of the ground; with rank vegetation, the germs of fever will invisibly grow and multiply; if he harbours that which is rotten and corrupt, he is himself consumed by those agents destined to remove the rottenness and corruption; it is a part of the law of nature that there should be active and energetic agents for this purpose. The seeds of disease, like the seeds of plants, may be shewn to have {vii} their indigenous localities; like them they may be spread and multiplied; like them they may lie dormant, and after awhile spring as it were into active existence; like them, when the soil and other conditions favour, they are ever ready to make their appearance. And this is the law, the germs of all disease exist, and have existed. Despise the dictates of nature, be careless of yourself and those around you, neglect to use the means which a n.o.ble intelligence has placed at your command, and above all, transgress the laws of G.o.d, then will disease pursue and attend you, as the conscience of the murderer pursues and attends him until he is finally cut off.

His wants and necessities, his sufferings and privations, are the basis of the intellectual progress of man. The wonders of Omnipotence are revealed through the whirlwind, the storm, the pestilence, and the famine.

The constructive and perceptive faculties of man have been developed by the necessity of protecting himself from injury by winds and rains; his intellectual faculties have been cultivated, by the sufferings of disease having led him to the study of {viii} organization and life, to discover the cause,--and to chemistry, and other sciences for the cure of his ailments.

Famine and distress have aroused his emotions, and softened down his asperities, so that what appears at first to be the infliction of a Curse without Pity, is in reality a Judgment with Mercy.

It occurred to me, that on the formation of the Epidemiological Society, the first question for consideration should be, What is the nature of those agents, which induce Epidemic Diseases? are they composed of animate or inanimate matter? In other words, do the manifestations of these diseases exhibit the operations of living or of chemical forces.

Having, in my study, dwelt on the subject with an earnest desire to find the truth, I put the suggestion, with my ideas, before the public to reject or receive them. If they be rejected, I can but think a full discussion of the enquiry will lead to the most important results. If they be received with favour, I doubt not others, with more ability, will take up the strain and resolve the discords into harmony.

J. G.

_Wandsworth, September, 1850._

INTRODUCTION.

It is one thing for a man to convince himself, but a very different thing to be able to convince others.

I am not now speaking of a conviction arising from the impression made by a few startling facts, nor of one forced on the mind by early prejudices, or by the dogmas of the schools, but of a conviction arising from careful enquiry.

In the course of that enquiry, the collector of facts, sees their relations to the idea in his mind, in a multiplicity of ways, from their remaining, each, as one succeeds the other, an appreciable time on the sensorium, and undergoing a certain process of comparison and relation, with all other facts and ideas which have been previously stored up. As the materials for an edifice which have been shaped and prepared in accordance with the completion of the design, so do the facts and ideas which are acc.u.mulated {2} in the mind, become shaped and prepared for the elimination of a truth.

The ultimate design of the architect can no more be conceived by the examination of the framework of a window, or the capital of a column, than the whole truth of a proposition by the examination of separate facts; the whole must be conceived and all the relations of all the parts thoroughly understood, before the architect can be comprehended or the harmony of his design appreciated.

The process of thought in the minds of the architect, and in the framer of a proposition, is never exactly the same as in those who contemplate and examine their completed works. Much may be done, however, by both to aid others in comprehending them. The more accurately they keep in view the course their minds have taken, the more readily will their descriptions be understood.

To simplify the elements of our knowledge is to give others a ready access to our thoughts.

To arrange the course of our ideas in harmony with the elements of our knowledge should be the end of all writing, as it is the only means of multiplying knowledge. {3}

It is not the mere acc.u.mulation of facts which const.i.tutes science, any more than a collection of building materials const.i.tutes a house, it is the arrangement and adaptation of the means to the end by which the house becomes built and science cultivated.

These reflections have been suggested by the circ.u.mstance that for the last 3000 years and upwards, Pestilences have at certain intervals done their work of destruction, and opened the springs of misery to untold millions, and yet I see not that we are much further advanced as to the knowledge of the cause of these inflictions than the Jews in the time of Moses. In the Levitical law, as I shall have occasion more particularly to shew hereafter, were directions specially given in reference to the plague of leprosy; what means should be adopted for the cure of the disease, and for preventing its extension, and moreover pointing very significantly to certain facts having connexion with the cause of the affection. Since that time historians generally, and medical writers in particular, have diligently recorded their observations and acc.u.mulated facts, on the various desolating plagues which {4} have afflicted mankind. Some of these men have grappled with the whole subject, and endeavoured to shew the presumed relation of the supposed causes in all their intricacies, but it is hardly necessary to say that all have signally failed in their attempts to furnish us with any practical information.

Satisfied in my own mind that the whole subject is beyond the labour of one man, and impressed with the belief that the basis of the enquiry is in anything but a satisfactory state, I have applied myself entirely to the study of the groundwork only, as the primary proceeding for a solid superstructure.

The days are past, when imaginary spirits, ethers, and astronomical phenomena, were believed to have any essential influence over our destinies in a physical point of view; we have therefore to deal with _matter_ in some form or other.

The question, therefore, which I have proposed for enquiry, is, whether the matter which causes epidemic and endemic diseases, exhibits the properties of inorganic or organized matter.

The properties and qualities of organized {5} bodies, as well as those of inorganic matter, need but be stated, and in some instances we may picture to ourselves the object, without having seen it, and not be very far from a true conception. But for this purpose a clear and definite idea must be previously formed, and have taken possession of the mind, of the great general divisions of objects in the material world.

Having made these preliminary remarks, I have suggested a certain mode of procedure in making enquiries of this kind, not perhaps in strict accordance with logical systems, but on the principle of nature's operations in our own minds, which appears to me, when reduced to a systematic and simple form, to be sufficiently clear and strict for synthetical application, and so concise as to be usefully and practicably applied.

In endeavouring to establish a theory for the explanation of extraordinary phenomena, there are certain rules which should guide us in the th.o.r.n.y and treacherous path of speculation. But these rules readily flow from the train of thought, and if we examine our own minds during their operations, we {6} shall find that the following is the course of our instinctive reflections. It is a course we adopt as the test of theories when formed, and is a guide in all cases for their construction.

We first commence with an idea, which exists in our minds in the form of a proposition: then the following rules naturally suggest themselves:--

1. The probability of the value of our proposition from inference.

2. The number and value of facts to support the proposition.

3. The reasonableness of the application of the facts to the inference.

4. What amount of information in the form of results can be produced in proof of the tenableness of the proposition.[1]

In ill.u.s.tration of the value of these rules the history of Dr. Jenner's discovery affords an appropriate example. To use the words of Dr. Gregory, "he appears very early in {7} life to have had his attention fixed by a popular notion among the peasantry of Gloucestershire, of the existence of an affection in the cow, supposed to afford security against the Small Pox; but he was not successful in convincing his professional brethren of the importance of the _idea_."

The popular notion of the peasantry originated the idea in Jenner's mind, and it became fixed there as a proposition.

1. He commenced his enquiry by observing that the hands of milkers on the dairy farms were subject to an eruption, and he _inferred_ that the notion of the peasantry bore the stamp of probability, which strengthened the idea in his mind and gave force to the proposition.

2. His next step was to acc.u.mulate facts; he found on enquiry that the persons engaged on these farms in milking, possessed an immunity from Small Pox to an extent sufficient to strengthen the value of his proposition.

3. The reasonableness of the application of the facts to the inference is clear from the coincidence that the eruption on the hands of the dairy people bore a striking {8} resemblance to the Small Pox, and as this disease does not usually occur twice in the same individual, the inference was most reasonable that this eruption protected the people from Small Pox.

4. We have but to take the almost universal adoption of vaccination, and its acknowledged prophylactic powers against the propagation of Small Pox to shew the application of our fourth rule.[2]

Between the conception of the idea and the accomplishment of Jenner's designs, vaccination seems to have undergone an incubation of nearly twenty years. During that period, with an energy and perseverance only to be obtained by confidence, did this great man brood over and elaborate his idea; and well might the 14th day of May, {9} 1796, be styled the birth day of vaccination, for on that day was a child first inoculated from the hands of a milker.

In adopting the above method I have endeavoured to bear in mind M.

Quetelet's observations on the requirements necessary for medical authorship; he says, "All reasonable men will, I think, agree on this point, that we must inform ourselves by observation, collect well-recorded facts, render them rigorously comparable, before seeking to discuss them with a view of declaring their relations, and methodically proceeding to the appreciation of causes."

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