894 Tbaxsactioxs of tse Americak Institute, 



fered more or less severely from cholera or diarrhea. Among the fatal 

 cases were those of twenty-live girls and nine boys, and the compara- 

 tive immunity of the latter, notwithstanding the yet more limited 

 dimensions of their school-rooms, aftords a remarkable confirmation 

 of the general doctrine here advanced; for we learn that, although 

 good and obedient in other respects, they could not be kept from 

 breaking the windows, so that many of them, probably, owed their 

 lives to the better ventilation thus established. 



" Now, in the goal of the same town, in which every prisoner is 

 allowed from 819 to 935 cubic feet of air, and this is continually 

 renewed by an efficient system of ventilation, there was not the 

 slightest indication of the epidemic influence. 



" The other ease to be here cited, is at the Millbank prison, in which 

 the good efitects of the diminution of previous overcrowding, were 

 extremely marked. In the month of July, 1849, when the epidemic 

 was becoming general and severe in the metropolis, the number of 

 onale prisoners Avas reduced by the transfer of a large proportion of 

 them to ShornclifF barracks, from 1,039 to 402; the nwmhQT oi female 

 prisoners, on the other hand, not only underwent no reduction, but 

 was augmented from 120 to 131. Now, the cholera mortality of Lon- 

 don generally, which was 0.9 per 1,000 in June and July, increased 

 to 4.5 per 1,000 in August and September; and the mortality among 

 the female prisoners underwent a similar increase^ from 8.3 to 53.4 

 per 1,000. But the mortality among \\\Qmale prisoners exhibited 

 the extraordinary diminution from 23.1 per 1,000, which was the rate 

 during June and Jul}-, when the prison was crowded, to 9.9 per 1,000, 

 which was its rate during August and September, after the reduction 

 had taken place. It is scarcely possible to imagine a more probative 

 case than this ; since it shows, in the first place, the marked influence 

 of the crowded state of the prison upon the fatality of the disease ; 

 secondly, the diminution of mortality among the male prisoners, con- 

 sequent upon the relief of the overcroAvding, notwithstanding the 

 quintupling of general mortality of the metropolis during the same 

 period ; and thirdly, the yet greater increase of mortality among the 

 female prisoners, which proved that the diminution among the males 

 could not be attributed to any recession of the epidemic influence 

 from the locality.'' 



From the very full and careful statistics prepared by the surgeon- 

 general of the armies of India, I find the mortality from cholera 

 varied as the provision for ventilation varied. Every other circum- 



