CHAPTER III.

GENERAL DISEASES RUNNING A DEFINITE COURSE.

1. THE GREAT PLAGUES.

In the nomenclature of the Royal College of Physicians, on the lines of which, with few exceptions, I, as a rule, proceed, the general diseases that affect mankind, as apart from the local conditions of disease, are divided into two grand classes: namely, into diseases which run a definite course, and take, some of them, an epidemic or spreading character: and into diseases which are not spreading, but are of a constitutional and often of an hereditary nature. I propose in the present chapter to state the diseases of the first of these classes, the epidemics or great plagues. They are defined, authoritatively, as follows:

Diseases "which appear to involve a morbid condition of the blood; which, for the most part, but not all of them, run a definite course; are attended with fever, and frequently with eruptions on the skin; are more or less readily communicable from person to person; and possess the singular and important property of generally protecting those who suffer them from a second attack." These diseases have each a period, between the time when they are first contracted and the first appearance of eruption or other symptom, which is called the period of incubation. Some of these diseases have also what is called a critical day or crisis, upon which the patient either begins to succumb or

commences to recover.

The diseases of this class are thirty-seven in number. They are, emphatically, the great plagues. They are all dependent for their development on some particular poisonous agent which is generally communicable from the affected to other susceptible persons.

SMALL-POX. VARIOLA.

An extremely contagious affection, marked by an eruption over the body containing matter or pus, and called pustules. The period of incubation is twelve days. The crisis is about the eighth day of eruption, but is not very definite.

Varieties.

Distinct. Each pustule of the eruption distinct. Confluent.-Pustules very numerous and running together over the surface of the body.

Semi-confluent.-Pustules running together in parts.

Abortive, varicelloid.-Minor small-pox. Few pustules, and those little more than vesicles,-little bladders,-containing watery fluid.

Petechial.-Called, vulgarly, black or putrid small-pox, dark blood being effused into the pustules.

Hemorrhagic.-Small-pox with blood in the pustules, with a tendency to bleeding from the mucous membrane of the intestinal canal.

Corymbose. The disease with the pustules running in clusters like bunches of grapes.

A disease induced in the human subject by the process of vaccination. A modified form of small-pox, in which a cow-pox vesicle on the udder of a cow or heifer is the common original source of the infecting matter. A disease attended, as a rule, with no further eruption than the vesicle or pustule at the points where the matter is inoculated; communicable by inoculation, but not otherwise; mild in its course, and yet, generally speaking, protective against small-pox. The period of incubation is from two to three days. The crisis is about the eighth day.

A disease attended, like the small-pox, with a vesicular eruption, which may become pustular. The spots of the eruption. usually lie far apart, and are confined to the trunk of the body. In bad forms varicella so closely resembles small-pox as to require skilled medical knowledge to distinguish it. The disease is

attended with some fever, but is hardly ever fatal, and rarely leaves pits or marks on the body. It is not prevented by vaccination, and it is not protective against small-pox. It is also doubtful whether small-pox is protective against it. It is not communicable by inoculation. The period of incubation is from ten to twelve days. The crisis is about the fifth day of the eruption.

MEASLES. MORBILLI.

A common and well-known eruptive contagious affection common to the young, and occurring in all parts of the world into which it may be imported. The disease is attended with a general red measly eruption and fever, preceded by symptoms of catarrh or cold in the eyes and nose. Under conditions favorable for recovery it is not generally fatal, but it becomes very fatal under unfavorable conditions. The period of incubation is from ten to fourteen days. The crisis,—not very definite,—is about the fourth day of the eruption.

GERMAN MEASLES. RÖTHELN. RUBEOLA.

A contagious mild disease, attended with slight fever, sore throat and measly oval-shaped red eruption. The affection, which usually commences with catarrh of the nose and eyes, presents mixed symptoms of measles and of scarlatina. The period of incubation is from four to six days. The crisis is on the second or third day of the eruption.

SCARLET FEVER. FEBRIS RUBRA.

A very contagious and often fatal disease, marked by a universal red rash over the body with high fever, strawberry tongue, and with redness and, sometimes, ulceration of the throat. The period of incubation is usually considered six to eight days, but may be not more than as many hours. The natural crisis is about the fifth day of the eruption, but is often prolonged by complications.

Varieties.

Simple Scarlet Fever.-Commonly called Scarlatina. The rash on the body is well marked, and the throat is very red but is not ulcerated.

Anginose Scarlet Fever.-A more severe type; the throat is

red, swollen, and ulcerated, with formation, sometimes, of abscess in the neck.

Malignant Scarlet Fever.--Scarlet fever in its most rapid and fatal form. In this variety the throat becomes covered with a slough from quick decomposition of the mucous membrane; the eruption on the skin is dark; the fever intense; the external glands of the throat are much enlarged; and, the prostration, sudden and severe, is attended often with convulsive movements of the limbs, with insensibility, coma and death. As a general rule the malignant form of scarlet fever is developed from the onset, and it may be said, generally, of each variety that, with rare exceptions, each maintains its own character and runs its This is true of epidemics as of individual instances of the disease. At the same time all the varieties are contagious, and one may be caught from the other, the severe form from the milder form, the milder form from the severe, or the like from the like. Constitutional peculiarity seems to determine the type which the disease will assume.

own course.

Sub-Varieties.

Doubtful Scarlet Fever. Rosalia Idiopathica.-A disease described originally in my Clinical Essays, in which a scarlatinal eruption occurs with some fever, soreness of the throat, and strawberry-like tongue. The disease is transient in character, does not spread, and apparently is not contagious. The period of incubation is probably from one to two days. The crisis is on the second day of the eruption. The disease is not known to be fatal.

Rheumatic Scarlet Fever.-A mixed condition of rheumatic and scarlet fevers,-also defined in the Clinical Essays,-in which, with the symptoms either of simple or of anginose scarlet fever, there is acute rheumatism of the joints. The scarlatinal element of the disease is contagious. The period of incubation is the same as of scarlet fever. The crisis is rendered indefinite by the frequent recurrence of rheumatic complications.

DENGUE. DANDY FEVER.

A febrile contagious disease, attended with rheumatic symptoms and with an eruption resembling measles. It occurs in the West Indies and in some other hot or tropical climates. The

period of incubation is short, probably not more than three days. The crisis is rendered indefinite by the recurrence of rheumatic symptoms.

CEREBRO-SPINAL OR TETANOID FEVER.

Cerebro-spinal fever is sometimes called malignant purpuric fever; or epidemic cerebro-spinal meningitis. More recently it has been named by Dr. Rosenstein, and as I venture to think most correctly, tetanoid fever. It has been known to occur in England. It is marked by a dark eruption, intense fever, delirium, and tetanic spasms. It is very fatal. The periods of incubation and of crisis are not determined. It is probably not contagious.

TYPHUS FEVER.

A continued fever attended with a dark mottled rash on the body, great nervous prostration and delirium, but without any specific affection of the bowels. The disease is very contagious, and very fatal. The period of incubation is, in most cases, from ten to twelve days. The crisis is about the fourteenth day after the eruption.

TYPHOID OR ENTERIC FEVER.

Typhoid or enteric fever, called also gastro-enteric,—owing to the circumstance that in it the stomach and intestines are seats of disease, is marked by a rose-colored rash on the skin, high fever, delirium, and much disturbance of the bowels. Until comparatively modern days typhus and typhoid fevers were confounded together as one disease, in the same way as measles and scarlet fever once were. Typhoid is now known as a distinct affection, and is distinguished from typhus by the occurrence of special intestinal derangement as well as by the eruption. It is not so readily contagious as typhus. The period of incubation ranges from six to fourteen days. The crisis is about the fourteenth day after the eruption. Typhoid, owing to its common connection with bad drainage, has received the vulgar but expressive name of "drain or cesspool fever."

RELAPSING OR FAMINE FEVER.

A fever which breaks out in ill-fed, badly-housed, or rather closely-housed communities. In some respects it resembles ty