Page:Encyclopædia Britannica, Ninth Edition, v. 12.djvu/562

546 546 HYDROPHOBIA contained in the secretions of the mouth of the affected animal into a wound or abrasion of the skin or mucous membrane. In the great majority of cases (90 per cent.) this is due to the bite of a rabid dog, but bites of rabid cats, wolves, foxes, jackals, &c., are occasionally the means of conveying the disease. There is no evidence that the poison can be introduced into the system without an abrasion of the surface. But it must be observed that even of those who have undoubtedly been bitten by rabid animals, only a proportion subsequently suffer from hydrophobia. Thus where the bite has been inflicted on a part of the body pro tected by clothing, the virus may be wiped from the teeth of the animal before they penetrate the skin. Hence it is found that bites on exposed parts such as the face are very much more dangerous than on other parts which are ordin arily covered. But further, individual susceptibility must be taken into account, for it is undeniable that many persons in whom the virus of rabies has been inoculated escape hydrophobia. John Hunter mentions one remark able instance in which of twenty-one persons bitten by a rabid dog only one subsequently died from hydrophobia ; and a comparison of the best authorities would seem to show that the proportion of those who are attacked with the disease to those who are bitten is less than one-half, Numerous popular fallacies prevail on the subject of hydro phobia, Thus it is supposed that the bite of an angry dog may produce the disease, and all the more if the animal should subsequently develop symptoms of rabies. The ground for this erroneous notion is the fact, which is unquestionable, that animals in whom rabies is in the stage of incubation, during which there are few if any symptoms, may by their bites convey the disease, though fortunately during this early stage they are little disposed to bite. The bite of a non-rabid animal, however enraged, cannot give rise to hydrophobia. Another fallacious notion, not alto gether of popular origin, but maintained by a few eminent professional authorities, is to the effect that there is no such disease as hydrophobia at all, but that the symptoms desig nated by that name are entirely mental phenomena produced by the effect of fear of the consequences following a bite. It might be sufficient as a reply to this to point to the uni form sequence of terrible symptoms which mark the pro gress of the malady when it has commenced, and to its acute course and invariably fatal termination ; but there is the additional fact that very young children, in whom this feeling could scarcely be expected to operate, may suffer and die from hydrophobia. The period of incubation of the disease, or that time which elapses between the introduction of the virus and the development of the symptoms, appears to vary in a remark able degree, being in some cases as short as a fortnight, and in others as long as several months or even years. On an average it seems to be from about six weeks to three months. The rare instances of the appearance of hydro phobia many years after the introduction of the poison are always more or less open to question as to subsequent inocu lation. During the period of latency, in which the patient seems perfectly well, it is supposed that the poison is under going a sort of multiplication, both in the previously wounded part and in the system at large, somewhat analo gous to the f ermentive process, and that ultimately it comes to tell with deadly effect upon certain portions of the nervous system. When the disease is about to declare itself it not unfre- quently happens that the wound, which had quickly and entirely healed after the bite, begins to exhibit evidence of irritation or inflammatory action, or at least to be the seat of morbid sensations such as numbness, tingling, or itching. The symptoms characterizing the premonitory stage aregreat mental depression and disquietude, together with restless ness and a kind of indefinite fear. There is an unusual tendency to talk, and the articulation is abrupt and rapid. Although in some instances the patients will not acknow ledge that they have been previously bitten, and deny it with great obstinacy, yet generally they are well aware of the nature of their malady, and speak despairingly of its consequences. There is in this early stage a certain amount of constitutional disturbance showing itself by feverishness, loss of appetite, sleeplessness, headache, great nervous excitability, respiration of a peculiar sighing or sobbing character, and even occasionally a noticeable aversion to. liquids. These symptoms constituting what is termed the melancholic stage continue in general for one or two days, when they are succeeded by the stage of excitement ill which all the characteristic phenomena of the malady are fully developed. Sometimes the disease first shows itself in this stage, without antecedent symptoms. The agitation of the sufferer now becomes greatly in creased, and the countenance exhibits anxiety and terror. There is noticed a marked embarrassment of the breathing, but the most striking and terrible features of this stage are the effects produced by attempts to swallow fluids. The patient suffers from thirst and desires eagerly to drink, but on making the effort is seized with a most violent suffocative paroxysm produced by spasm of the muscles of swallowing and breathing, which continues for several seconds, and is succeeded by a feeling of intense alarm and distress. With great caution and determination the attempt is renewed, but only to be followed with a repetition of the seizure, until the unhappy sufferer ceases from sheer dread to try to quench the thirst which torments him. Indeed the very thought of doing so suffices to bring on a choking paroxysm, as does also the sound of the running of water. The patient is extremely sensitive to any kind of external impression; a bright light, a loud noise, a breath of cool air, contact with any one, are all apt to bring on one of these seizures. But besides these suffocative attacks there also occur general convulsions affecting the whole muscular spasm. These various paroxysms increase in frequency and severity with the advance of the disease, but alternate with intervals of comparative quiet, in which, however, there is intense anxiety and more or less constant difficulty of breathing, accompanied with a peculiar sonorous expira tion, which has suggested the notion that the patient barks like a dog. In many instances there is great mental dis turbance, with fits of maniacal excitement, in which he strikes at every one about him, and accuses them of being the cause of his sufferings, these attacks being succeeded by calm intervals in which he expresses great regret for his violent behaviour. During all this stage of the disease the patient is tormented with a viscid secretion accumulat ing in his mouth, which from dread of swallowing he is constantly spitting about him. There may also be noticed snapping movements of the jaws as if he were attempt ing to bite, but these are in reality a manifestation of the spasmodic action which affects the muscles generally. There is no great amount of fever, but there is constipa tion, diminished flow of urine, and often sexual excitement. After two or three days of suffering of the most terrible description the patient succumbs, death taking place either in a paroxysm of choking, or on the other hand in a tranquil manner from exhaustion, all the symptoms having abated, and the power of swallowing returned before the end. The duration of the disease from the first declaration of the symptoms is generally from three to five days. Post-mortem examination has not hitherto thrown much light upon this malady, but the subject is at the present time engaging the special attention of certain eminent J pathologists, and important and valuable information may
 * system of the body, and occasionally a condition of tetanic