68 Public Parks. 



The high temperature and dry south-west wind had already 

 paved the way for this great mortaHty ; and when to this was added 

 the moist warm north-east wind, all the atmospheric conditions were 

 prepared, and it onlv needed the presence of cholera to make it 

 epidemic. Secretion of the skin was checked, the lungs were called 

 upon to throw off an unusual amount of carbonic acid, thus reducing 

 the vital powers, and the bowels were necessarily requii'ed to excrete 

 more, and with what effect is but too well-known. This stillness of 

 the atmosphere continued for three days, when, on the 14th, more 

 activity was perceptible, with an abatement of the epidemic. The 

 ratio would still be more marked, had a record been kept of all that 

 died. That portion of the table referring to 1S67, may be regai'ded 

 as nearer the normal condition than that of either ''66 or ^6^. The 

 general health was remarkably good, but in 1868, there was a great 

 increase of mortality, without any epidemic tendency, and the causes 

 of which will be alluded to hereafter. 



The table on page 62, shows the influence of Lake Michigan 

 and of the cardinal winds upon life. It will be seen that more 

 deaths occurred in 1866, when the westerly -winds prevailed, and in 

 the autumn, than at any other season ; also, in winter and spring, and 

 that the greatest mortality occurred in summer by the southerly 

 winds, and the least when easterly winds prevailed. In 1867, the 

 mortality was more equally distributed between westerly and easterly 

 winds, and the greatest number of deaths occurred during the pre- 

 valence of westerly winds, and in summer ; and that the least 

 mortality took place in the spring, the season of the 3'ear when the 

 causes of death are less rife than any other, unless more than 

 ordinary conditions obtain. In 1868, the greatest mortality occurred 

 during the prevalence of easterly winds, and in summer. This year, 

 also, differs from the other years by the unusually great mortality 

 that occurred in winter. 



By reference to the table on page 63, will be seen the influence 

 of temperature and rain on mortality, by seasons. During the 

 winter of 1S66, it was cold, and great mortality occurred during the 

 westerly winds, not much rain falling ; in spring, it was warm, and 

 the mortality was greater than usual, particularly when the north- 

 west wind prevailed ; the summer was cold, and a large quantity of 

 rain fell, and deaths took place proportionably ; and in autumn it 

 was unusually warm, a large amount of rain also falling; cholera 

 prevailed, and the greatest mortality took place when the wind was 



