TABLE XLIII.-Average atmospheric pressure for months and year 1903, at each of 6 stations in Michigan; also averages for 5 stations, as indicated by the height, in inches, of Mercury in the barometer. Corrected for temperature. Reduced to 32° F. (for some stations not corrected for instrumental errors*).-Average of observations made daily at 7 A. M., 2 P. M. and 9 P. M. by observers† for the State Board of Health. d Traverse City. N W. b 29.390 9 Harrisville N. E. 24 Thornville.. B. & E. 22 Agricultural College.. C. 25 Lansing, S. B. of H.. C. 23 Ann Arbor. S. C. 29.034 29.178 29.305 29.427 29.226 29.284 29.318 29.309 29.192 29.308 29.450 29.267 29.397 29 260 29.265 29.303 29.372 29.344 29.328 29.227 b 28.954 28.948 28.861 28.979 29.089 28.890 29.047 28.920 28.946 28.947 29.049 28.952 28.887 28.809 29.072 28.984 28.865 29.022 29.105 28.873 29.041 28.985 28.922 28.956 29.058 29.017 29.015 28.946 29.065 29.081 28.962 29.083 29.204 29.008 29.143 29.026 29 057 29.064 29.161 29.135 29.112 29.020 29.041 28.925 29.013 29.167 28.934 29.143 28.978 29.022 29.021 29.130 29.095 29.077 28.990 29.073 28.961 29.081 29.203 28.994 29.154 29.034 29.042 29.058 29.154 29.109 29.084 28.998 * A correction has been made for instrumental error of barometer at Ann Arbor; .004 has been added to each monthly average during the year 1903. At the Agricultural College, -.013 has been subtracted from each monthly average. For other stations the instrumental error of barometer is not known. †The names of observers, their places of observation, and the counties in which these places are situated are stated in Table I. The full names of divisions and the counties in each division are stated in Exhibit I, in the annual report for 1898 and preceding reports. § Numbers in this column state the average annual atmospheric pressure for periods of years ending in each case with December 31, 1903. The small figures at the right of the numbers which state the average denote the number of years included in the average. This line is an average for 5 stations, at which observations, nearly complete, were received for every month in the year. It does not include Traverse City. Green's standard barometer was used at all the six stations for 1903. The average for 11 months is 29.303. Health. NOTE.-Computations of monthly averages for the year 1903 were furnished by the observers at Ann Arbor. The remainder of the computations were made at the office of the State Board of a For 28 days. b For 26 days. c For 25 days. d For 23 days. The average line and lines for five stations in this table are graphically represented in Diagram XVI. DIAGRAM XVI. ATMOSPHERIC PRESSURE, BY MONTHS, 1903. AVERAGE BARDMETRIC PRESSURE.-AT STATIONS IN MICHIGAN. AGRICULTURAL COLLEGE ---- ; ANN ARBOR HARRISVILLE; LANSING -oxoxoxoxoxTHORNVILLE-X-X--X TABLE XLIV.—Average daily range of atmospheric pressure, by year and months, in 1903, compared with annual and monthly averages for 1902, and for the 21 years, 1882-1902.* These averages are for groups of several stations in Michigan. *At from 5 to 18 stations per year for the twenty-one years, 1882-1902. Just which stations in each year, up to 1897, are shown on page 78, report for 1898. TABLE XLV.-Range of atmospheric pressure, by year and months, in 1903, compared with annual and monthly averages for 1902, and for the 21 years, 1882-1902.* These averages are for groups of several stations in Michigan. 1902 (5 stations). 1903 (4 stations) .690 1.049 .808 1.191 .954 1.187 1.564 1.301 1.087 .638 .825 .540 .570 *At from 5 to 18 stations per year for the twenty-one years, 1882-1902. Just which stations in each year, up to 1897, are shown on page 78, report for 1898. Sunshine and clouds.-On the back of each blank register supplied by this Board to observers, on which they are to register meteorological data, is a statement that "One observer has reported a record of days 'all or nearly all cloudy' and days 'all or nearly all sunshine.' The State Board of Health would be glad to have such a report from all observers who can conveniently make it. Memoranda may be made in a column headed 'cloudy or sunny,' days more than eighty per cent of clouds being marked with the abbreviation 'C,' indicating cloudy, and days with less than 20 per cent of clouds with an 'S,' indicating sunshine." Table XLVI, exhibits the results of such observations at nine stations in Michigan, for the several months in 1903. TABLE XLVI.-Statements of the number of days in each month which were reported" sunny," "partly cloudy," and "cloudy," by observers at stations in Michigan. THE TIME OF GREATEST PREVALENCE OF EACH DISEASE. CONTRIBUTIONS TO THE STUDY OF THE CAUSATION OF SICKNESS. A STATISTICAL REPORT BASED ON WEEKLY POSTAL-CARD REPORTS OF SICKNESS IN MICHIGAN DURING THE YEAR 1903, AND COMPARISONS WITH PRECEDING YEARS. COMPILED UNDER THE DIRECTION OF THE SECRETARY OF THE STATE BOARD OF HEALTH. This paper is the twenty-seventh in a series of articles upon the same general subject begun in the latter part of 1876. It presents a summary of the compilation of weekly reports of sickness in Michigan in 1903. It includes a series of graphic illustrations which show by months, in 1903, the rise and fall of twenty-eight of the most prominent diseases in Michigan. The value of sickness statistics is indicated on page 702 of "A Manual of Practical Hygiene," by Chas. Harrington, M. D., Assistant Professor of Hygiene in the Medical School of Harvard University, as follows: "Registration of Sickness, if it were possible, would afford a far more efficient index of the sanitary condition of the population than the registration of deaths, which gives us simply the number of cases of sickness which ended fatally, but no idea of the duration thereof or of the number of persons temporarily incapacitated. A disease ordinarily regarded as fairly dangerous may prevail very extensively in a mild form, and be attended by a very low death-rate, and, again, may exist to a lesser extent, but in an unusually severe form, with a high proportion of fatalities. Many diseases, again, are temporarily disabling and often widely prevalent, but play a small part in mortality returns. Tonsillitis, for example, is responsible for much discomfort and lost time; its prevalence has some meaning, but its death roll is exceedingly small. Rheumatism is much more widespread than mortality returns would imply; chicken-pox is relatively unimportant, but in some places its notification is required as a safeguard against the spread of smallpox incorrectly diagnosed as varicella; gonorrhea, without being fatal, does more harm than commonly is supposed; and syphilis, also not immediately and directly fatal, sends its victims into the mortality returns through various avenues. The sickness statistics of Michigan are unique. There are no other sickness statistics in the world based upon weekly reports and covering any considerable area, for a long series of years, and showing the relation of each disease to season of the year and to each of the several meteorological conditions. The weekly reports of sickness, upon which this article is based, are made by representative physicians in active, general, practice; and an effort is made to obtain such reports from all parts of the State, so that they shall correctly represent the sickness which occurs. One of the objects of this compilation is to learn the time of the greatest and of the lease prevalence of each of the important diseases in the State, and the relative prevalence in each month, and to note the connection of this prevalence with each of the meteorological conditions in the State. Tables are given showing the per cent of the weekly reports and the per cent of observers which stated the presence of the various diseases; and by comparing Table 1 with Table 4, we see the correspondence in the two lines of evidence, |