phus, but differs in the absence of an eruption and in the circumstance that the onset is direct, i.e., without preliminary signs, and that the febrile attacks, usually of short though severe duration, pass away leaving the person comparatively well. After an interval of about seven days the attacks recur, the relapse taking place, it may be, four and even five times. The disease is less fatal than typhus fever, but recovery from it is often much more prolonged. It is extremely communicable, and attacks those who are well fed if they be exposed to its influence. It is connected with famine in its origin, but seems also to require impure air for its development. The period of incubation is from five to seven days. The period of crisis is indefinite.

FEBRICULA.

A minor fever, in which the person affected is for three or four days feverish without showing any signs of eruption on the skin or any indications of inflammatory disease, recovery being rapid and complete. The disease can hardly be called communicable, though it may be epidemic. The periods of incubation and of crisis are indefinite.

CONTINUED FEVER.

Simple fever, without eruption, inflammation, or other specific sign that would link it with any of the specifically contagious febrile diseases. It differs from simple febricula by its longer continuance. In past days physicians included many of the now well-defined fevers under the term continued fever, making it almost a general term to describe a fever that was of long duration. The periods of incubation and of crisis are undefined.

YELLOW FEVER.

"A malignant epidemic fever, usually continued, but sometimes assuming a paroxysmal type, characterized by yellowness of the skin, and accompanied, in the severest cases, by black vomit, hemorrhage from the stomach, nose and mouth." This is the terse description of the disease by the Royal College. It is peculiar to tropical climates, and does not spread in a temperature below 72° F. It is extremely fatal, perhaps communicable, and decidedly epidemic. The period of incubation is indefinite,

but probably not more than four days. The period of crisis is from six to eight days.

PLAGUE.

Plague is defined as "a specific fever, attended with bubo, 'boil,' of the inguinal glands of the groin," and other glands, and "occasionally with carbuncles." It is the pest or pestilentia, black death, of the old writers, and at one period it invaded this country, though it has always been chiefly confined to Eastern countries. It is easily communicable and extremely fatal. The periods of incubation and of crisis are very short, two to eight days, but have not been definitely assigned.

AGUE. INTERMITTENT FEVER.

A disease attended with paroxysms of severe fever, followed by intermissions of the febrile condition during which the sufferer, though he may be enfeebled, is comparatively well. The paroxysms are signalized by three stages, called respectively the hot stage, in which the fever may rise to 105° F.; the sweating stage, in the course of which, owing to the profuse loss of water from the body, the fever is reduced and the temperature brought down; the cold stage, in which the body is reduced in temperature to the natural 98.4°, and sometimes to a little below what is natural. The paroxysms thus developed recur with considerable regularity, not in all cases in the same order of time, but in the same case after the same order. Thus, in one case the paroxysm will recur daily, in another every third day, in another every fourth day,-in regular order. This has led to the enumeration of several varieties of the disease.

Quotidian, where the fit occurs every twenty-four hours while the disease lasts.

Tertian, where the fit occurs every forty-eight hours while the disease lasts.

Quartan, where the fit occurs every seventy-two hours while the disease lasts.

Irregular, in which the paroxysins are not distinctly periodical. Under this head the College includes the periodical neuralgia which is called brow ague.

In quotidian ague, the fit is most prolonged; it may last for sixteen hours during the three stages. In the tertian variety the

fit is of shorter duration, ten hours. In the quartan the fit is of shorter duration still, namely, six hours. Ague was once a common disease in England, and even in London. The great Lord Protector, Oliver Cromwell, succumbed to it, and in the time of His Highness and long afterwards the physicians had much practice from it. It declined in this country from two causes, from the drainage of fenny and marshy districts, and from the introduction of Jesuit's bark,-cinchona,-for its treatment. The disease seems to be entirely due to some miasmatic marshy poison which, disposed of largely during the paroxysm, re-forms in the body in the course of the interval of remission and reproduces the attack. The period of incubation is from one to fourteen days. The crisis in each fit is defined above. The general crisis is undetermined.

REMITTENT FEVER.

A fever occurring occasionally in this country, but more frequently in warmer climates, in which, with paroxysmal attacks of high fever, as in ague, but at less regular intervals, there is a yellowness of the skin something like that which characterizes yellow fever. The disease in temperate climates is sometimes. called "bilious remittent," and in tropical climates malignant remittent fever. It is rarely fatal in the milder forms of it, and is of local or endemic character, depending upon some malarious cause. It was remarked to me thirty years ago by an old practitioner, who in the fen districts had, in his early life, seen much of ague, that on cessation of that disease bilious remittent fever, which had also been common, remained much longer as a local disease. There are no definite periods of incubation nor of crisis.

SIMPLE CHOLERA.

Cholera, or relaxation of the bowels, with or without vomiting. The disease occurs in this and in other countries with a certain degree of seasonal regularity, and is marked by a copious loss of fluid from the intestinal canal, with, in bad cases, cramps in the bowels and limbs and coldness of the body, followed, during recovery, by reactive fever. The affection, which is not contagious, occurs at times epidemically, and is not infrequently fatal. From its common appearance in the autumn, it is sometimes called autumnal cholera. It is usually excited by indulgence in

some form of indigestible foods, such as unripe fruits, but there is, at the same time, a presiding influence promoting the tendency, which is probably atmospheric, but which is not as yet defined by scientific research. The period of incubation is usually short, not more than a few hours. There is no defined period of crisis.

MALIGNANT CHOLERA.

Specifically, the cholera. Called also Asiatic cholera, serous cholera, spasmodic cholera, and defined, graphically, by the Royal College as "an epidemic disease, characterized by vomiting and purging, with evacuations like rice water, accompanied by cramps, and resulting in suppression of urine and collapse." The disease is of Eastern origin, but has travelled over the temperate, and to some extent into the arctic zone. It is apparently communicable, seems to follow the courses of great rivers, and, according to the modern view, first advanced by the late Dr. Snow, the poison of it is conveyed mainly by water. It is extremely fatal, and attacks people of all ages, but men more frequently than women. Occasionally, it takes a sporadic form, breaking out, that is to say, in scattered places and then ceasing, without pursuing a definite course. The period of incubation is short, often not exceeding five or six hours. The crisis is indefinite.

DIPHTHERIA.

A disease which in many respects is allied to croup, but which differs from that affection in that it is of contagious character. It is attended with fever, which usually appears to arise from cold and sore throat, but which ends in a specific affection of the throat. In bad cases the windpipe and air-passages become covered with a tough membranous exudation, which may separate like a piece of leather from the mucous surface. Diphtheria is most frequent and fatal in children, but it attacks persons of adolescent and middle life, and it is extremely fatal. There are some persons who seem more susceptible than others to its influence, and there can be no doubt that the tendency to it runs in particular families. Although manifesting itself by the most marked local signs in the throat, it is a general disease in which there is a tendency to separation and coagulation of the fibrinous part of the blood. It is often rendered rapidly fatal by the separation and coagulation of the fibrine of the blood within the heart.

The period of incubation, according to my observation, is from three to six days. The crisis is about the fifth day.

Diphtheritic Paralysis.-Diphtheria is sometimes followed by paralysis of some of the muscles of the body. The palsy affects mostly the muscles used in swallowing, but it sometimes extends to the muscles of the neck, and even to those of the limbs. I have seen it once extend so as to include the whole of the muscles of the right side of the body. It is, I believe, due to a process of coagulation in the nervous fibres. As a rule persons of fair general health recover from it under conditions favorable for recovery.

WHOOPING-COUGH OR PERTUSSIS.

At

A disease beginning as a cold and attended with spasmodic cough coming on in paroxysms and often, by the violence of the cough, causing disease of the lungs. It is attended at first with some febrile disturbance, and in all stages it is communicable. the onset it is apparently confined to irritation in or near the glottis, the opening into the windpipe. The period of incubation is from four to six days. The crisis is indefinite, but the disease rarely lasts less than five weeks.

MUMPS.

An epidemic and probably a communicable disease, affecting the salivary glands. The glands are much swollen and inflamed, and there is a general feverish condition. It is rarely a fatal disease, but is often severely painful. The period of incubation is about fourteen days; that of crisis about four days.

INFLUENZA.

A suddenly developed and intensely severe cold or catarrh, hence sometimes called "lightning catarrh," attended with an extreme nervous depression and violent cough. It is often epidemic or spreading, but is not proved to be contagious. Sometimes it suddenly affects a whole community, and in many epidemic visitations has been extremely fatal. The period of incubation is a few hours. The crisis is indefinite.