distance. Whether the contagious particles are conveyed by the air itself or by the medium of the common household fly or other insects, the important fact remains that the infection may travel far. The influence of the Sheffield Hospital could be distinctly traced for a circle of 4,000 feet; for instance, the following percentages of households attacked at successive distances from the hospital are given in the original report 1:

0-1,000 feet.
1.75

1-2,000 feet.
•50

2-3,000 feet.
14

3-1,000 feet.
*05

Elsewhere.
*02

This possibility of small-pox spreading by aerial infection increases greatly both the hospital difficulty and that of individual isolation.

(283) The Duty of the Sanitary Authority and of its Medical Officer in Small-Pox Outbreaks.

It is specially in the first cases of small-pox breaking out in a town or district that energy and promptitude of action is necessary. The power of mischief that a single case will effect is well seen in the epidemic at the St. Joseph's Industrial School, Manchester, in 1888, in which an imported undiagnosed case infected at one time forty-six inmates and subsequently twenty-three others. It is also well shown in the following case taken from Dr. Birdwood's Report to the Asylums Board, 1888:

A primary duty is the removal of the patient to an infectious hospital, presuming the sanitary authority to possess one, and that one a sufficient distance from centres of population. Every one

1 "Report of an Epidemic of Small-pox at Sheffield, 1887-8." By Dr. Barry. Local Government Board. London, 1889.

2 Public Health, vol. i., 174.

8 See also the elaborate report of Mr. Power. "Statistics of small-pox incidence upon the registration districts of London relative to the operations of small-pox hospitals in the Metropolis, in a succession of chapters." By Mr. W. H. Power. Sixteenth Annual Report of the Local Government Board (Supplement).

in or around the house or coming to the house should be vaccinated. No person, whatever his position is in life, and however elaborate his nursing arrangements or so-called isolation may be, can be isolated satisfactorily in a private town house; hence, whatever the social position of the sufferer, if the law does not compel, he should at least be persuaded to allow himself to be put apart in a place remote from other habitations.

In many places of course there can be no removal, and in these the medical officer of health will have to exercise his personal authority, all his resources, and ingenuity. It may be possible to empty the house (after vaccination) of all the inhabitants save those nursing the sick: this is the next best thing to removing the patient himself. If there should be choice of a room, one at the top of the house will be preferable, and all unnecessary furniture should be removed, as well as all those carpets, rugs, clothes, curtains, and things not essential to comfort. All excreta should be received in a 1 per cent. solution of corrosive sublimate; the discharges from nose, mouth, or from the eruption generally, should be received on soft old rags and immediately burned. The patient should have a complete set of eating utensils, cups, saucers, &c., devoted to his exclusive use; there should properly be two nurses, one to relieve the other; special dresses or aprons should be supplied to all necessary visitors, who would cover their usual dress during the visit by wearing these garments. Before leaving, washing the hands and face should be insisted upon. The nurses should of course not wear the same dress out as in nursing the sick. In short, the strict management of an infectious hospital should be insisted upon. If the patient should die, the body should be covered with carbolised lime and early coffined. Cases of small-pox attended with delirium may be difficult to manage; the author remembers in his own experience such a case escaping from a house in Lisson Grove and walking down Bond Street, very likely infecting in his passage several people. In such cases personal temporary restraint is absolutely necessary. On convalescence being established a hot bath should be taken daily, and it may be well to oil the skin thoroughly, to wash the oil off, and finally to take a bath of corrosive sublimate solution, 1 per 1,000; there is no danger in such a bath, the solution being too weak to be absorbed in sufficient quantity to poison. After

taking the baths for two or three days, and clean, well disinfected or new clothing being put on, and every scab having fallen, it is probable that the patient is no longer infectious, and he may mix with other people. In those cases however in which the eruption only consists of some twenty or thirty spots, most of which do not go on to suppuration, it is not likely that the amount of infection can be so great as in the severe cases, and it may be safe to consider the case terminated at a shorter period than the month from the appearance of the eruption. There is indeed every probability that three weeks from the first eruption in mild cases may be, with the precautions indicated, a sufficient period of isolation.

(284) Vaccination and Small-Pox.

The experimental and statistical evidence as to the efficiency of vaccination in modifying, and in most instances entirely preventing small-pox, is of such a conclusive nature that it is difficult to see why it has been rejected by a section of the community. It is impracticable within the limits of this work to enter into the history of the subject, the last enquiry at Sheffield will therefore alone be summarized, the more especially as the results finally dispose of the assertion that the evident diminution of smallpox mortality is owing to general sanitary improvement rather than to vaccination.

Special instructions were given to Dr. Barry1 to observe and note carefully every influence that could bear upon the incidence of the epidemic in Sheffield, but no influence was found that had not been dominated by the single influence of vaccination. This' influence may be studied first in two great age-groups, and secondly as affecting the population of all ages and both sexes.

First, Children under 10 years of age.-Per thousand of the number of children in each class; the attack-rate of the vaccinated was 5; the attack-rate of the unvaccinated was 101; the deathrate of the vaccinated was '09; the death-rate of the unvaccinated was 44; or stated in other terms: for 100,000 vaccinated children the rate of small-pox mortality actually observed in Sheffield gives 9 deaths; for 100,000 unvaccinated children, the rate of small-pox

1 "Report on an Epidemic of Small-pox at Sheffield, 1887-8." Local Government Board, 1889. In the above Dr. Buchanan's summary is used.

mortality actually observed gives 4,400 deaths. The above relates to the general children population of the borough. Children living in houses actually invaded were of course exposed to an intenser and more continuous infection, but similar results were obtained thus: Per thousand of the number of children of each class living in invaded houses; the attack-rate of the vaccinated was 78; the attack-rate of the unvaccinated was 869; the death-rate of the vaccinated was 1; the death-rate of the unvaccinated was 381.

Secondly, Persons over 10 years of age.—(a) Under ordinary conditions, per thousand of the number of persons over 10 in each class: the attack-rate in persons twice vaccinated was 3; the attack rate in persons once vaccinated was 19; the attack-rate in persons not vaccinated was 94; the death-rate among persons twice vaccinated was 08; the death-rate among persons once vaccinated was 1; the death-rate among persons not vaccinated was 51. (b) Persons in invaded houses: the attack-rate of the vaccinated was 281; the attack-rate of the unvaccinated was 686; the death-rate of the vaccinated was 14; the death-rate of the unvaccinated was 371.

Influence of Vaccination upon the Attack and Death-rate of people of all ages living in Sheffield.—(a) Living under ordinary conditions: the attack-rate of the vaccinated was 155 per thousand; the attack-rate of the unvaccinated was 97·0 per thousand; the deathrate in the vaccinated was 7 per thousand; the death-rate in the unvaccinated was 480 per thousand. (b) Living in invaded houses: the attack-rate of the vaccinated was 230 per thousand; the attackrate in the unvaccinated was 750 per thousand; the death-rate of the vaccinated was 11 per thousand; the death-rate of the unvaccinated was 372 per thousand.

What was true of the fatality was found also true as to the virulence or otherwise of the attack. "From the experience of 1,741 patients treated in hospitals, Dr. Barry reported 17.2 per cent. of severe and confluent cases of small-pox in patients of all ages who had been vaccinated, and 81.5 per cent. of the same forms of small-pox, out of every 100 attacks in people of all ages who had not been vaccinated; for children under 10 the corresponding figures were 9 and 78.

"In the hospitals also the familiar immunity of re-vaccinated persons in attendance on the sick was observed. There were 161

persons employed in the wards and offices of five hospitals. Of the 161, 18 had had small-pox before their engagement, none of these fell ill; 62 persons had been vaccinated in infancy only, of these 6 were attacked, 1 died; the remaining 81 persons had been successfully re-vaccinated, not one of these contracted small-pox."

In the early days of vaccination it was stated to confer full immunity, we now know that this is not correct. Given that several years have elapsed since the vaccination, and that the person is exposed to a large dose of the poison, the disease may be contracted, and the same remark holds good with regard to first attacks of small-pox; the author has himself seen a person pitted from a former attack contract a second, and die. There are evidently some so constituted that protection is evanescent, but the majority are absolutely safe after a successful vaccination, from all ordinary infection, for an unknown and somewhat uncertain number of years. It is probable that re-vaccination every seven years of the population would extinguish small-pox altogether; in any case re-vaccination is to be advised by the medical officer of health, if he should1 have grounds for forecasting an epidemic, and certainly when an epidemic actually exists. It seems indeed monstrous that with this powerful agency at command, there should be any necessity for spending sums of money on small-pox hospitals, when a complete and thorough compulsory re-vaccination of the community would at once stamp it out. Re-vaccination must be considered in the light of a test—if the vaccination should "take," it is a sign that the infection of small-pox would also "take."

MEASLES.

Measles is a febrile exanthem, highly infectious, more especially prevalent in the early years of life, and but occasionally affecting adults; one attack gives immunity, as a rule, against a second.

(285) Statistics.

In this country measles is fatal to from six to fourteen thousand

1 Re-vaccination would be more sought by numbers of people were it not for the dread of "bad arms," and it cannot be denied that a largish proportion of re-vaccinations are followed by far more redness and unpleasant local sequelæ than primary vaccinations. The reason of this might well be a subject for careful inquiry in the laboratory of the bacteriologist.