PREFACE.
Thepresent work is a continuation of my treatises on collateral subjects, and, like them, maintains the opinion, that great epidemics are epochs of development, wherein the mental energies of mankind are exerted in every direction. The history of the world bears indisputable testimony to this fact. The tendencies of the mind, the turn of thought of whole ages, have frequently depended on prevailing diseases; for nothing exercises a more potent influence over man, either in disposing him to calmness and submission, or in kindling in him the wildest passions, than the proximity of inevitable and universal danger. Often have infatuation and fanaticism, hatred and revenge, engendered by an overwhelming fear of death, spread fire and flames throughout the world. Famine and diseases, among which may be instanced the fiery plague of St. Anthony, were no less powerful in calling forth the chivalrous spirit of the crusades than the enthusiastic eloquence of Peter the Hermit—the Black Death brought thousands to the stake, and aroused the fearful penances of the Flagellants—while the oriental leprosy cast a gloomy shade over society throughout the whole course of the middle ages.
With all such commotions, the most striking events of the world are in intimate relation, and unquestionably, amid the changing forms of existence in the human race, more has always depended on the prevailing tone of thought than on the rude powers by which those events were produced. The historian, therefore, who would investigate the hidden influence of mind, cannot dispense with medical research. The facts themselves convince him of the organic union of the corporeal and the spiritual in all human affairs, and consequently of the innate vital connexion of all human knowledge. Hence, in a medical point of view, how vast is the field for observationpresented by the history of popular diseases. Present bodily sufferings[1], are, collectively, but a step in the development,—but one phase of morbid life amid a long series of phenomena, and hence are not fully understood without a previous knowledge of the past, and historical research. How can we recognise the ring of Saturn as such, so long as our axis of vision is in its plane, and we see it only as a line. Great pestilences have vanished or been dispersed; from causes apparently the most insignificant, the most important consequences have resulted, and throughout the vicissitudes of danger and devastation, the operations of mighty laws of nature are everywhere manifested in the social tendencies of entire centuries.
This is no aërial realm of transitory conjectures—facts themselves speak in a thousand reminiscences. If we do but investigate the past with unprejudiced assiduity—if we do but consider even the few successful researches which have hitherto been made in historical pathology, (perhaps those who are kindly disposed will recognise even mine,) we shall not fail to arrive at a centre of reality, which the healing art, to its great detriment, has hitherto been far from reaching, whilst it has occasionally penetrated into a less fertile soil, or even encumbered itself with the accumulated rubbish of the pedantic dogmas of the schools.
The state, which founds its legislation on a knowledge of realities, which expects from the physical sciences information respecting human life collectively, considered in all its relations, has a right to demand from its physicians a general insight into the nature and causes of popular diseases. Such an insight, however, as is worthy the dignity of a science, cannot be obtained by the observation of isolated epidemics, because nature never in any one of them displays herself in all her bearings, nor brings into action, at one time, more than a few of the laws of general disease. One generation, however rich it may be in stores of important knowledge, is never adequate to establish, on the foundation of actually observed phenomena, a doctrine of popular diseases worthy of the name. The experience of all ages is the source whence we must in this case draw, and medicalinvestigation is the only road which leads to this source, unless, indeed, we would be unprepared to meet new epidemics, and would maintain the unfounded opinion that medical science, as it now exists, is the full result of all preceding efforts.
An insight, not only into general visitations of disease, which in the course of ages have appeared in divers forms, but also into every single disease, whether it occurs in intimate connexion with others or not, is rendered more distinct by a knowledge of the contemporary circumstances which attend its development. I would fain hope, therefore, that the future research and diligence of physicians devoted to the pursuit of truth and science, will be more generally directed to historical investigation; and that universities and academies will concede to it that prominent place, which, from its high importance, as an extensive branch of natural philosophy, it justly demands.
Whether the following inquiry into one of the most remarkable diseases on record corresponds with these views, I must leave my readers to judge. The historian will discern what social feelings are produced among nations by great events, and to the physician a picture of suffering will be unveiled, to which the diseases of the present time afford no parallel. I have throughout kept in view the spirit and the dignity of the sixteenth century, which was as remarkable for military triumphs as for tragic events; and I look with confidence for the same indulgence and goodwill now, which, through the kindness of friends, I have already enjoyed both at home and abroad, in a higher degree than my sincere gratitude can find words to express.