come established in only a few countries, notably in Ireland, Russia, and Italy, and even here they are of but limited extent. Telluric and seasonal influences do not appear to be of much, if any, importance in deciding an epidemic outbreak.

In 1883 a small epidemic of typhus fever occurred in the Philadelphia Hospital, and in 1881 to 1882 over 700 cases were admitted to the Riverside Hospital in New York. Other than these, there have been no outbreaks of any moment in this country since those that occurred between 1867 and 1870.

Dissemination.-Typhus fever is highly contagious, in the strict sense of the word, and there is probably no disease that has been more frequently contracted from patients by physicians and nurses. The specific virus, of whatever nature it may be, appears to be distinctly transmissible from the sick to the well through the surrounding air. Whether it is usually received by way of the air-passages, or through the alimentary tract, or whether infection may occur through wounds, cannot be stated, as nothing is known of the causative agent.

The poison may be harbored by and carried from place to place in fomites. As stated, the activities of the specific virus are favored by unsanitary conditions, and if cases of the disease be introduced into overcrowded, filthy, and generally unhygienic localities, there is every likelihood of an epidemic outbreak of the fever. By some writers it is believed to be carried from the sick to the well by insects.

The disease is less common among the very young and the aged than during the periods of youth and early maturity. Its occurrence is not influenced by sex.

Prophylaxis.-It is manifest that the most important prophylactic measures against this fever are those that aim to prevent its introduction from without, and those that are designed to eliminate all local conditions favorable to its development.

The former comprise the functions of such properly constituted systems of quarantine as should exist at all populous seaports; the latter represent the duties of legally author

ized boards of health. The scope of the work should embrace the strict sanitary supervision of overcrowded localities, such as exist in all the poorer districts of great centers of population, and should be especially directed to the general hygiene of places designed for both permanent and temporary residence by people of such localities—as, for instance, tenement-houses, work-shops and work-houses, jails, reformatories, almshouses, and hospitals. Especial attention should be given to the cleanliness, the ventilation, the condition of crowding, the water-supply, and the sewage of these places. Careful watch should be kept for the occurrence of suspicious cases, and these should be isolated in properly equipped hospitals as soon as detected.

The influence of fresh air upon the virulence and vitality of the virus of this disease is apparently of very great importance, and many of those who have observed the epidemic outbreak of typhus fever in hospitals have been struck by the rapidity of its disappearance when the patients were removed from the wards and placed in tents in the open. Isolation in freely ventilated apartments, and careful disinfection of bedand body-clothing and excreta are always called for. Isolation should be rigidly enforced, because of the highly contagious nature of the disease; and for the same reason the physician and attendants should spend no more time than is necessary in the immediate proximity of the patient.

The sick chamber, as well as all furniture and other articles contained in it, should be disinfected and thoroughly aired after the removal of the patient.

RELAPSING FEVER.

Definition.-" Relapsing," "Famine," or "Seven Days' Fever," is an infectious disease that results from the presence in the blood of a specific micro-organism discovered by Obermeier and now generally known as spirocheta Obermeiri.

The disease is characterized by acute febrile paroxysms that last from six to seven days. These are followed by an intermission of the same length of time, when the acute symptoms reappear. It is from the occurrence of these relapses that the fever takes its name.

The organism causing the disease is a spiral-shaped thread that may be seen moving about among the corpuscles in blood drawn during the paroxysms (Fig. 27). They disap

pear from the blood until the crisis of the fever, and are but very rarely to be detected during the period of intermission. In dried blood preparations the spirochæta may be stained by the usual methods. It is decolorized by Gram's method. It varies in length, being sometimes hardly longer than the diameter of a red corpuscle, while at other times it is many times this length. Nothing is known of its life history. It has never been reared artificially.

By inoculation with blood from these patients the disease

has been induced in men and in monkeys, though in the latter only the primary acute fever occurs and there is no tendency to recur. The organism has been kept alive outside the human body for about a week, by keeping on ice leeches that have been allowed to fill themselves with blood from these patients, and it has been observed by Tictin alive in the bodies of bedbugs forty-eight hours after they had filled themselves with blood containing it.

The conditions that favor the development of typhus fever -viz., squalor, filth, destitution, etc.-likewise favor the development of relapsing fever, and the two diseases have been observed together in the same locality.

Distribution.-Quoting Hirsch, the first trustworthy account that we have of this disease on European soil is given by Rutty in 1770 in his chronological history of the prevailing diseases of Dublin. In this publication he directs attention to an epidemic of this fever that occurred in Dublin in 1739. The fever has been more prevalent in Ireland, Scotland, Russia, parts of Germany, northern Africa, and India than elsewhere. It had not appeared in Australia up to 1875. It was first observed in this country, in Philadelphia, in 1844. It has not appeared in the United States in epidemic form since 1869, when it prevailed extensively in New York and Philadelphia.

It is not apparently influenced by age, sex, season, or telluric conditions, though it is said to have occurred more frequently in the temperate and cold than in warm climates.

Dissemination.-It is said to be contagious, though less so than is typhus fever. The causative agent is said to be transmissible by fomites. In view of the fact that the disease may be induced through the direct inoculation of healthy persons with the blood of those suffering from the disease, it has for some time been thought that blood-sucking insects may be important factors in its dissemination. In 1897, Tictin' brought forward important experimental evidence in support of this opinion. He found that the dis

1 Tictin, Cent. f. Bact. u. Parasitenkunde, 1897, Erste Abtheilung, Band xxi., S. 179.

ease could be produced in monkeys by inoculating them with the contents of bedbugs that had gorged themselves with blood containing the specific organism. This was possible only in those insects that had recently fed; in those kept for forty-eight hours the organism, though still apparently alive, was incapable of lighting up the disease. He calls attention to the prevalence of insects of this class in the places in which he observed the disease to originatenamely, in asylums, almshouses, boarding- and lodginghouses frequented by the filthy, ragged, and destitute. He believes infection may occur both by the bite of the insect and by crushing them and rubbing their contents into small wounds of the skin made during the act of scratching.

Prophylaxis.-Since the social conditions that favor the development of typhus likewise favor the development of relapsing fever, the prophylactic measures recommended for the former serve equally well for the latter disease.

RABIES.

(Lyssa; Hydrophobia.)

Definition, Cause, etc.-A specific infectious disease communicable from animals to animals and to man, commonly by a bite.

When occurring in animals it is known as rabies or lyssa; when in man, as hydrophobia, not because of the actual fear of water, as the name signifies, but rather because of the dread felt by the patient of the severe spasm of the muscles of deglutition that is experienced in efforts to swallow water.

In the rabid animal the virus of the disease is contained in the saliva, and it is through wounds made with the teeth, or wounds to which saliva from such animals gains access, that rabies is transmitted.

Numerous efforts have been made to detect the etiological factor of rabies, but as yet no trustworthy results have been