OF ATMOSPHERIC CHANGES UPON DISEASE.' 173 



in the mean temperature of the preceding week (to 6° 

 below the average). 



In the week ending August list the departure from our 

 rule is very slight; the disease curve continues to fall 

 together with the temperature, apparently in consequence 

 of the continued influence of the heat of the preceding 

 weekj which is 3"5° above the average. 



In the week ending September i^th the disease curve 

 rises, and in that ending October 2nd it falls in accordance 

 with the curve of temperature, but in the latter instance the 

 preceding high temperature seems to display its influence. 



Out of the seventy-nine weeks which we have now 

 examined, twenty-three (29 per cent) exhibit departures 

 from exact accordance with our rule ; but, as we have seen, 

 most of these are still to be accounted for on the supposi- 

 tion that the mean temperature influences the progress of 

 the disease; but it seems probable that other elements, 

 such as N.E. winds, also exercise some efiect. 



Bronchitis and Catarrh. 



The curve of these diseases, although drawn from ten 

 times the number of cases, is almost identical with that of 

 pneumonia, its highest and lowest points coinciding exactly 

 with those of the pneumonia curve. 



It will be unnecessary, therefore, to trace it throughout 

 its course, since it is evidently affected by temperature in 

 much the same way as pneumonia. 



The correspondence of the mean temperature curve with 

 that of bronchitis is even closer than with that of pneu- 

 monia, the exceptions being only 26^ per cent. 



It may be observed that in the year 1857, when the 

 disease curve marks a deviation from the rule of tempera- 

 ture, it may generally be ascribed to a change in the degree 

 of humidity, the disease curve rising as the amount of 

 moisture diminishes, and vice versa. 



