102 



The largest number of cases of 



Hoemorrhage (28) occurs at 30*150 inches. 

 „ Apoplexy (16) „ 30-200 „ 



„ „ Abortion (7) „ 29-900 „ 



„ „ Neuralgia (53) „ 30 150 „ 



Of Neuralgias also 51 eases occur at 30-000 inches; 50 at 

 30*200 inches (29*950 inches being the mean height of the 

 barometer.) 



Other charts were exhibited, which had been drawn to 

 ascertain whether the extent of barometric oscillation between 

 two successive days, had any predisposing influence upon these 

 diseases — with respect to hoemorrhage, no such influence could 

 be traced; and neuralgias occurred much more frequently 

 when the fluctuations of pressure were comparatively small. 



With respect to apoplexy, the enquiry was carried further, 

 in consequence of a statement that " of the number of cases of 

 apoplexy which occurred (at Hawarden) in the years 1850 and 

 1851, 50 per cent took place on days of decreasing reading 

 of the barometer, and 50 per cent on days after such reading." 

 Of 177 cases of apoplexy, 91 occurred with decreasing 

 readings, 87 with increasing readings of the barometer ; and 

 of the 87 cases, 44 occurred on days immediately succeeding 

 days of decreasing readings, 43 on days succeeding others of 

 increasing readings. 



The sources of error from the influence of warmth or 

 moisture were examined, but no efl*ect was traced to these 

 causes, except in the case of apoplexy. 



The following conclusions were drawn from the investi- 

 gation : 1. That a high degree of barometic pressure is 



favourable to the production of neuralgias, less evidently so to 

 apoplexies and other hncmorrages, and that abortions are not 

 shown to be affected by it. 2. That increasing readings of 

 the barometer are as frequently accompanied by cases of these 

 diseases as decreasing readings. 3. That a small extent of 

 diurnal oscillation of the barometer seems to be favourable to 



