Dr. Benjamin Lee, in an elaborate paper, read before the American Public Health Association, November 11, 1875, figures up the cost of the small-pox epidemic in Philadelphia, 1870-71-72, at $16,835,977. 9 (excluding his item "loss by death.") In that epidemic there were 20,065 cases, with 4:64 deaths-making an average cost per case of $839.12, actual and constructive cost both included. On the same basis the 6588 cases in Chicago, covering a like period of time, would have cost $5,528,122.66.

A word or two of comment may be permitted, before closing this summary, concerning these economic features of the epidemic.

Up to the middle of January, 1882, a few days before the date of the Secretary's letter to Dr. Stephen Smith, already quoted, there had been 126 outbreaks in the State at large, or about 10 per month, the average duration of which was 71.5 days each; subsequent to that date, and up to the last of December, 1883, there were 180 more outbreaks (7.6 per month), the average duration of which was 30.6 days each. Dividing on the same period, there were 1,235 cases, with 271 deaths, before January 15, 1882; and 805 cases, with 18 deaths, after that date-giving averages, per month, of 98.8 cases, with 21.7 deaths, and 34.2 cases, with 7.1 deaths, for the two periods, respectively.

Had the epidemic continued at the same averages after January 15, 1882, as obtained prior to that date, the aggregate would have been 3,557 cases, with 780 deaths, instead of 2,040 cases, with 460 deaths, as reported. There would have been £60 outbreaks, averaging 71.5 days each, making an aggregate of 25,740 days' duration; instead of 206 outbreaks, averaging 47.4 days each, and an aggregate of 14,520 days' duration.

A comparative statement of cost would present the following contrasts, dealing only with the State at large, and exclusive of Chicago:

*Estimated at 20 per cent. less than cost of cases treated in the State at large.

This item is obviously much too low; but, in the absence of other data for an estimate, the per diem cost in the State at large is used, furnishing this result.

It should be noted that this showing does not take into account the fact that, as vaccination and revaccination were more generally resorted to; as methods of dealing with an outbreak improved; as local authorities became more familiar with their duties and responsibilities; in short, as the agencies which the BOARD set in motion at its November, 1881, meeting, came to be felt throughout the State, panic, alarm, excitement, were less easily aroused; cases were promptly and more economically cared for; quarantines of exclusion were less frequen ly enforced; schools, churches, courts, and other public assemblages, were maintained, even though a case or two of small-pox existed in the community, where, in the earlier days, they would have been summarily closed; travel, traffic, and business generally, went on with little or no interruption; and the disease, from about the middle of January, 1882, lost significance as a dreaded epidemic.

That these results, and this constructive saving of 320 lives, 1,517 cases, and over two and three-quarter millions of dollars, were due solely to the efforts of the STATE BOARD OF HEALTH, it is not assumed to claim. It is something more, however, than a coincidence, that, within twenty days from the time when the efforts. of the BOARD may be fairly supposed to have begun to act, there should have been the sudden and marked decline shown in the foregoing figures and tables. And, making all legitimate deduction for the operation of other causes in the production of this result, a sufficient margin of credit will still remain to satisfy the thoughtful investigator of the utility, the necessity, and the economy of a central, co-ordinating agency, with power to direct, ability to instruct, and means to supplement and assist the independent efforts of local authorities. These latter are usually adequate to cope with the ordinary sanitary problems. But to successfully resist or suppress an invasion of epidemic contagious or infectious disease, demands disciplined, organized, co-operative action, such as it has been found possible hitherto to secure only through a central State organization.

TABLES, NOTES AND COMMENTS.

Of the total number of cases reported to the BOARD, the data of 1,931 were sufficiently full and trustworthy to warrant their use in the following tables. These have been framed mainly with the view of illustrating the question of vaccinal protection, and such illustration is presented in fuller detail, it is believed, at least in some phases, than ever before attempted. As examples, Table II, having reference to the period of vaccination in relation to exposure; Tables III and IV, analyzing the mortality in the general class "Unvaccinated"; and Table VI, dealing with vaccination in relation to puberty-may be cited in the following group.

The first table gives the general results for the entire period, 1881-1883; and the general results for each of the three groups, Vaccinated, Unvaccinated, and Miscellaneous.*

TABLE I.-Showing Actual Mortality and Mortality Per cent. of all Vaccinated-Unvaccinated-Miscellaneous.

One anomalous feature of the epidemic should be noted in connection with this table: Contrary to the general experience in prolonged epidemics, the mortality rate increased, instead of diminishing, toward the close. In 1881, the mortality rate was 21.. per cent. ;

*For typographical convenience, the signs plus (+) and minus (−) are employed, instead of decimals, and have this signification: Where the decimal is greater than 50, the next higher whole number is used with the minus sign; where it is less than 50, the whole number only is used, followed by the plus sign. Thus, the percentage of total recoveries in the 1,931 cases is written 76+, instead of 76.17; and the percentage of total deaths is written 24-, instead of 23.82.

in 1882, it rose to 24.8 per cent., and, in 1893, to 25 per cent. This in the State at large. În Chicago the mortality followed the usual rule, being 39.37 per cent. in 1881 (43.42 per cent. among cases treated at home, and 31.7 per cent. among cases treated in hospital); in 1882 it fell to 35.77 per cent. (39.5 per cent. among cases treated at home, and 28 per cent. among hospital cases); and, in 883, there was a further decline to 25.8 per cent. (28.4 per cent. among at home cases, and 20.9 per cent. among hospital cases.)

Three factors probably combine to reduce the mortality rate, in prolonged epidemics of contagious or infectious diseases, as the epidemic continues. First: The individuals most susceptible to the contagion are the first attacked among those exposed; and such hyper-susceptibles succumb in larger numbers than do those whose powers of general and special resistance are greater. Second: There would seem to be a diminution of virulence in the contagion produced by its passage through numbers of individuals. Jenner was convinced that this was true of the small-pox contagion; and although Pasteur and others have failed to demonstrate this by recent experiment, there is much in the history of epidemies of other diseases besides small-pox-notably, for example, in many yellow-fever epidemics-tending to confirm Jenner's views. It is possible, also, that the continued exposure of the less susceptible, who finally yield to an attack, begets in them a tolerance of the poison which modifies the severity of its effects. Third: As an epidemic progresses, both diagnosis and modes of treatment sensibly improve; and thus not only is the actual mortality rate diminished, but a very important element of error in computing the mortality rate is eliminated, to-wit the failure to recognize and report mild or obscure cases of the disease. Such failures obtain the more extensively as the disease is of rare occurrence-whence arises want of familiarity with its diagnostic features; or, where advertisement of the disease is followed by unpleasant results, as in placarding the infected house, quarantining or isolating the compromised, removal of the infected to hospital, loss or interruption of business, etc. Both these causes combine to swell the apparent mortality rate in the early period of a small-pox epidemic; during which period it not unfrequently happens that the first notification of the existence of a case is the burial certificate.

The departure from this rule in the State at large during this epidemic, is found on examination to be more apparent than real. During the first year Chicago, and the territory immediately adjacent or in close communication therewith, furnished the greatest number of cases. While the disease continued, to a greater or less degree, in this original territory, it extended during the second year to the middle and southern portions of the State; and, during the third year, invaded areas still more remote from great lines of travel. So that, in reality, the disease can be said to have existed. as a three years' epidemic only in Chicago; while in the State at large successive portions were invaded only for brief periods-the disease, as a rule, being promptly suppressed, notwithstanding its frequent introduction, wherever the rules and regulations of the STATE BOARD were adopted and enforced.

Under this view of the question, there still remains to be considered the fact of a successively-increasing mortality rate, in what may be regarded as three distinct epidemic periods and distinct epidemic areas in the State at large. This, however, is believed of be fully accounted for by the difference in the vaccinal status of the areas infected. In those traversed by the great trunk lines of travel, and in direct and constant communication with Chicago, St. Louis and other large cities, the evidence is conclusive that vaccination is much more uniformly resorted to, and that a higher degree of vaccinal protection is secured, than in the more remote and secluded regions.

The case, then, may be thus summed up: During the first year of the disease in the State at large, the population of the areas then infected was better protected against small pox by general vaccination, and, consequently, exhibited a lower mortality rate, as compared with the population of the areas infected during the second year; and this latter compared more favorably in both respects, although not to so marked an extent, with the population in the areas infected during the third year-the mortality percentages being as before stated, 21.9, during the first year, 1881; 24.8, during the second year, 1882; and 25 during the third year, 1883.

TABLE II.-Showing Recoveries and Deaths-with Percentages-among 1081 Successfully Vaccinated Cases, Analyzed with Reference to Date of Vaccination in Relation to Exposure.

Sexes and Percentages.

Successfully
vaccinated.

Before expos-
ure only.

After exposure.

Both before and after exposure.

Tot'l Rec. Died. Total Rec. Died. Tot'l Rec. Died. Tot'l Rec. Died.

NOTE-Total "recovered, before exposure only," includes 41 males and 52 females, on whom revaccination after exposure is reported unsuccessful. Total "die, before exposure only," includes 5 males and 7 females, the same. Total "recovered, after exposure only." includes 1 male and 7 females, on whom revaccination before exposure is reported unsuccessful.

The absolute protective power of vaccination is strikingly shown. in the above table. Only 65 cases of the disease, out of the total 1,9 1 cases tabulated, occurred among those who had been vaccinated, both before and after exposure, and all of these recovered, This protective power is also seen to bear a relation, in point of time, to the nearness of the vaccination to the date of attack. Of those vaccinated "before exposure only," 93.18 per cent. recovered; while of those vaccinated "after exposure only," 9.42 per cent. recovered. The obvious lesson of these figures is: It is never too late to vaccinate.