VITAL STATISTICS, JANUARY TO JUNE, INCLUSIVE, 1906.

The figures heretofore given have had reference to the calendar year 1905. In order that this report may be brought as nearly up to date as is practicable, the following summary is published to show roughly the trend of our mortality during the current year. No effort has been made to compute death rates, as half-yearly death rates would probably be confusing owing to the effect of season on mortality and to the likelihood of confounding such death rates with those computed on the basis of the year's returns. The proper basis for the computation of such death rates is the returns of the police census of May 22, 1906. For the convenience of any who may wish to compute such rates the following synopsis of such returns is published:

Summary of results of the police censuses of the District of Columbia of April 12, 1905, and May 22, 1906.

As shown in the foregoing statement, the increase in the population of the District since 1905 is small, but a little over 1 per cent. This increase was due almost altogether to an increase in the number of persons more than 20 years of age. There was an increase in the white population amounting to almost 4,000, but the colored population show a net diminution of 677.

The mortality record shows that there has been a slight increase in the number of deaths reported during the first six months of 1906 as compared with the corresponding period of 1905. The percentage of increase has not been quite so large, however, as the percentage of increase in the population. Marked increases occurred in the number

Increase.

Decrease.

1905.

1906.

1,622

All.

Increase.

91

Decrease.

of deaths from measles, whooping cough, diarrheal diseases among children under 2 years of age, and typhoid fever. There were decreases in the number of deaths from pulmonary tuberculosis, pneumonia, and bronchitis.

Relative mortality during the first six months of the calendar years 1905 and 1906.

The following tables show the absolute and the relative extent to which the various reportable communicable diseases prevailed in the District of Columbia during the calendar year 1905, and the severity of the prevailing type. During the first half of the current year there has been an increased prevalence of diphtheria and of typhoid fever, but a diminished number of cases of scarlet fever has been reported. A detailed report upon the operations of the contagious-disease service and of the disinfecting service appears in the appendix, in the report of the inspector having charge of such work.

Statement showing the prevalence and severity of diphtheria, scarlet fever, typhoid fever, and smallpox during the calendar year 1905, with comparative figures for previous years.

a Cases not reported until February 26, 1902; deaths occurring in 1902 were after that date. For a statement of death rate see pages 310-311.

Typhoid fever.-The first filter for our public water supply was put into operation August 18, 1905, but it was not until October 5 that raw water was cut off entirely from the mains and the entire water supply filtered. The figures given above with reference to typhoid fever do not carry the record beyond December 31, 1905, and therefore could not be expected to show anything as to the effect of the filtration on the prevalence of that disease in this jurisdiction. Unfortunately, however, even now the record of cases reported fails to show that filtration has in any way reduced the prevalence of typhoid fever in this jurisdiction. The following table shows the distribution of typhoid fever by months and by years since July 1, 1902. The act requiring cases of typhoid fever to be reported to the health department became operative February 4, 1902, but the reports received prior to July 1 of that year are probably too incomplete to afford a safe basis for comparison with corresponding figures for subsequent years.

Statement showing the prevalence of typhoid fever in the District of Columbia, by months and by years, since July 1, 1902.

NOTE.-On October 20, 1906, of cases reported in April, 4 were still under treatment; in May, 12; in June, 47; in July, 4; in August, 69; in September, 74.

The geographical distribution of typhoid fever in the District during 1905 is shown in Table 7e on page 296, and on one of the maps appended to this report. For further data relative to typhoid fever during the past year, reference should be made to the report of the inspector in charge of the contagious-disease service in the Appendix. Among persons whose zeal to defend the good name of the city of Washington exceeds their knowledge of the facts of the case, it is commonly asserted that a large number of the cases reported as typhoid fever are not typhoid fever but other diseases mistakenly diagnosed by attending physicians. If we might assume that our local physicians are prone to make mistakes when undertaking to diagnose typhoid fever, yet it would not appear how such errors would result oftener in filing erroneous reports than in the failing to report genuine cases. It is not unlikely that for every case erroneously reported as typhoid fever at least one case of typhoid fever passes unrecognized and unreported. And if cases are reported as typhoid fever that are not that disease but some other, there is no material difference in the gravity of the situation; for from 13 to 14 per cent of all reported cases die. The ordinary percentage of fatalities among cases of typhoid fever is given by Osler (Practice of Medicine, 1906 edition) as 5 to 12 in private practice and in hospital practice from 7 to 20, and by Nothnagel (Encyclopedia of Practical Medicine) as from 9 to 12 per cent, and at most 14 per cent.

Another popular explanation of the prevalence of typhoid fever in this District is that a large number of the cases that occur here have their origin elsewhere, and this hypothesis has some foundation in existing facts. Those who cling most closely to this theory commonly fail to carry it to its logical conclusion. Every case of typhoid fever reported to the health department has been carefully studied to determine its origin if possible, and a certain number has been traced with reasonable certainty to sources outside of the District of Columbia. But the number of cases that were contracted in the District and developed elsewhere is not known and serves to offset in whole or in part the cases imported here.

Occasional outbreaks have been met with that were traceable directly to milk infection, but no reason has ever appeared for regarding the

milk supply as the sole or even as the chief cause of typhoid fever in this community. Not only is the theory of the origin of typhoid fever in our milk supply not reasonably consistent with the facts pertaining to that supply, but it is inconsistent with the fact that no reduction in the prevalence of typhoid fever has resulted from the improvement of the dairies and dairy farms from which our milk supply is derived. And no matter what view one may take of the present status of the milk supply of the District of Columbia, it may unhesitatingly be asserted that its present condition is vastly superior to its condition ten years ago.

Our public wells have been charged with responsibility for the prevalence of typhoid fever within the District. But a vast majority of the patients who have suffered from typhoid fever have not used well water, as has been definitely ascertained by inquiries made for that purpose. There is no grouping of typhoid cases in the vicinity of public wells, and the reduction in the number of shallow public wells from 216 on June 30, 1894, to 62 on June 30, 1902, was accompanied by no reduction whatsoever in the prevalence of the disease. It is true that on the date last named 40 deep wells had been put into use, but even if the fact be ignored that the water from these wells was at that time of exceptional purity the number of such wells was not nearly large enough to offset the number of shallow wells abandoned.

I have chosen to refer to the status of typhoid fever on June 30, 1902, when speaking of the effect of the closing of wells, rather than to refer to the present time, because during the calendar year 1903 there occurred a sudden diminution in the prevalence of typhoid fever and the lower rate then established has been maintained during 1904 and 1905, but has not been progressive. This improvement, whether real or apparent, is, I believe, in some way connected with the enactment, on February 4, 1902, of the law requiring all cases of typhoid fever to be reported to the health officer. There is certainly no discoverable reason for believing that it was in anyway connected with the antecedent closing of public wells, or that it was due to the fact that by June 30, 1906, the total number of public wells had been reduced to 85, of which 53 were shallow and 32 deep.

Attempts have been made by some observers to charge our typhoid fever to box privies that still exist, infection being supposed to spread either through the agency of flies or through neighboring wells. As has been pointed out above, it is impossible to connect our public wells with the prevalence of typhoid fever, and the number of private wells in the city is very small. And so far as the fly theory is concerned, it is utterly impotent to explain the prevalence of typhoid during the cold season, when flies are dormant in the cold atmosphere of the outof-door privy and have a minimum of activity even within the warmer dwelling.

While the registration of privies is as yet admittedly imperfect yet a sufficient number has been registered, it is believed, to afford a general index to the distribution of privies throughout the District, and the most careful study of the distribution of box privies has failed to show any connection between it and the incidence of typhoid fever in the locality. In fact, so far as any difference can be observed those districts in which there are the most box privies seem to be rather freer from typhoid fever than do other places, which condition prior to the filtration of our water supply was attributed by the health department