Note on Contagion and Infection.

There are no words in regard to which there is more misconception, or more nonsense talked and written, than the two words “contagion” and “infection;” and as the word “infectious” has been used in these Notes, it is necessary to say what it does mean, and what it does not mean. The word “contagion” appears to have been first used by certain classical writers to signify the spread of scab among sheep; and it would have been well for humanity if the word had been restricted to this very primitive bucolic signification. It was not till centuries after Virgil’s death that the common sense of men had descended so low as to introduce it into the Medical vocabulary. This took place at a period when, from the neglect of sanitary arrangements, pestilence attacked whole masses of people, and when no one appears to have considered that nature had any laws for her guidance whatever. It was not until human intelligence had descended to this depth that men seem to have bethought themselves of Virgil’s term as affording them an adequate explanation for pestilence, and sufficient reason for not exerting themselves to prevent its recurrence. So it has continued ever since. The little word used in all innocence by the poet for poetic purposes has become the ground-work of every manner of false observation, false reasoning, neglect of sanitary laws, lazarettos, quarantine, and continually-threatened interruption to the commercial intercourse of mankind. No single word has ever done so much harm to the human race, or given such a proof of what a mighty thing a word is!

One would have thought that, after the sanitary experience of the last fifteen years, the word “contagion” would have disappeared from our language; but, even in the last document issued by the expiring Board of Health, written by their Medical Officer, Mr. Simon, and based on erroneous statistical evidence (Papers relating to the Sanitary state of the People of England, 1858), it is stated that “a further—practically speaking, unavoidable—cause of premature death in every civilized country is the risk of its current contagions.” [The italics are not mine.] And this refers to small pox, hooping cough, measels, and scarlatina, the mortality from which we are to presume, is “unavoidable.”

If this be Board of Health doctrine, it is certainly not sanitary doctrine. It would have astonished the Health of Towns Commission, and the first Board of Health.

“Contagion,” as its etymology implies, means the communication of disease from person to person by contact. It is often confused with “infection;” but it has quite a different meaning. Contagion presupposes the existence of certain germs, like the sporules of fungi, which can be bottled up and conveyed any distance, attached to clothing, merchandize, especially to woollen stuffs, for which it is supposed to have a particular affection, and to feathers, which of all articles it especially loves, so much so that, according to Quarantine laws, a live goose may be safely introduced from a plague country; but, if it happens to be eaten on the voyage, its feathers cannot be introduced without danger to the entire community. The absurdities connected with the doctrine are numberless. Suffice it to say that in the ordinary sense of the term there is no such thing as “contagion.” There are two or three diseases in which there is a specific virus which can be seen, tasted, smelt, and analysed, and which, in certain constitutions, propagates the original disease by inoculation, such as small-pox, cow-pox, and syphilis, but these are not “contagions” in the sense supposed.

With regard to the mysterious, imponderable, indivisible nonentities, which make up our “current contagions,” they may safely be dismissed into the limbo of extinct superstitions.

The word “contagion” therefore is altogether objectionable.

The word “infection” expresses a fact, without involving a hypothesis.

It is most necessary, however, that the meaning should be guarded; for, just as there is no such thing as “contagion,” there is no such thing as inevitable “infection.” Infection acts through the air. Poison the air breathed by individuals and we have infection. Shut up 150 healthy people in a Black Hole of Calcutta, and in twenty-four hours you have an infection produced, so powerful that it will in that time have destroyed nearly the whole of the inmates. Sick people are more susceptible than healthy people; and if you shut up sick people together, without a sufficient space and sufficient fresh air, you will have not only fever, but erysipelas, pyæmia, and the usual tribe of Hospital-generated epidemic diseases produced.

Again, if we have a Fever Hospital with over-crowded badly-ventilated wards, or with the air stagnant in them, we are quite certain to have the air become so infected as to poison the blood not only of the sick, so as to augment their mortality, but also of the medical attendants and nurses, so that they shall also become subjects of fever.

It will be seen at a glance that, in every such case and in every such example, the infection is not inevitable, but the simple result of gross carelessness and ignorance. In certain Hospitals it has been the custom to set apart wards for what are called “infectious” diseases; but, in reality, there ought to be no diseases considered such. It follows from what has been stated that, with proper sanitary precautions, diseases reputed to be peculiarly “infectious” may be treated in wards among other sick without any danger; just in the same way as, with proper sanitary precautions, a number of healthy people may be congregated together without becoming subject to the horrors of the Black Hole of Calcutta.

It is in the highest degree probable that we should never have heard of “infectious” wards, if the other wards of a Hospital had been supplied with sufficient space and air for the sick; and in too many cases it is to be feared that the presumed “infectious” cases are huddled away into small, ill-lighted, ill-ventilated rooms, a kind of Lazaretto, in fact, where, if they die, they have at least been kept from doing harm to the other sick in Hospital!

It is high time that common sense should deal with the question; for there does not seem to be much hope for a deliverance from these superstitions from any other quarter.

The “infectious” wards in Military Hospitals correspond, in some sense, to the “casualty” wards in Civil Hospitals, into which accidents, noisy, and erysipelatous cases are transferred, when necessary. The advantages of a separate set of wards for this class of cases have been already insisted upon in these Notes; not certainly because the cases are inevitably “infectious,” but because the segregation of such facilitates greatly administration and nursing, while it removes offensive and noisy patients out of the Hospital wards, whose inmates they would annoy. The question of infection or non-infection has nothing to do with the arrangement. No stronger condemnation of any Hospital or ward could be pronounced than the simple fact that any disease has attacked other patients than those first affected by it. “Infection” and incapable management, or bad construction, are, in Hospitals, convertible terms.

It may be useful to mention what the meaning is of the words “epidemic,” “endemic,” “sporadic,” and “zymotic.”

When a large number of people are attacked simultaneously with the same form of disease it is said to be epidemic. When a small number, as, e. g., the inhabitants of a single court or alley, are so attacked, it is said to be endemic. When scattered cases of the same disease happen, one here, one there, over a large surface, the disease is said to be sporadic. The term zymotic, which includes all diseases of the preceding categories and some others, implies the existence of certain changes in the constitution or in the blood, rendering persons so affected liable to the diseases in question.

It is a vulgar error to suppose that epidemics are occasioned by the spread of disease, from person to person, by infection or contagion; for it is an ascertained fact that, before any people is attacked epidemically, the disease attacks individuals in a milder form, one at a time, at distant intervals, for weeks or months before the epidemic appears. Before an epidemic of cholera, these cases consist generally of diarrhœa of more or less intensity, followed by a rapidly fatal case or two, very much resembling cholera. Even plague itself, as in the recent epidemic at Bengazi, begins with cases which cannot be distinguished from ordinary typhus-fever, the succeeding cases getting more and more intense, until the epidemic seizure takes place. Experience appears to show that without this antecedent preparatory stage, affecting more or less the entire population of a town or district, the occurrence of an epidemic is impossible—the epidemic being, in fact, the last or, so to speak, the retributive stage of a succession of antecedent phenomena extending over months or years, and all traceable to the culpable neglect of natural laws. It is simply worse than folly, after the penalty has been incurred, to cry out “contagion,” and call for the establishment of sanitary cordons and quarantine, instead of relying on measures of hygiène. Epidemics are lessons to be profited by: they teach, not that “current contagions” are “inevitable” but that, unless nature’s laws be studied and obeyed, she will infallibly step in and vindicate them, sooner or later.

In the words of the Registrar-General, which are as applicable to Armies as to States, “Sanitary measures and not quarantines are the real safe-guards of nations.”