21 



reach its acme in the autumn. But the reverse takes place. 

 During our quarter of extreme heat our deaths are fewest ; 

 therefore, we cannot suppose our summer is inimical, hut 

 friendly, to the patients, and must credit it with its own 

 minimum mortality. And when we review the cases that have 

 fallen under our notice, we must remember how these patients 

 nearly always enjoy the hot weather more than any other 

 season of the year, and require medical services less. 



If we throw the monthly deaths from phthisis into the form 

 of percentages, and so facilitate a comparison with the monthly 

 mortality from all diseases, the special influence of the summer 

 upon consumption hecomes more evident. 



20S per 1,000 of the deaths from phthisis occur in December, 

 January, and February. 



285 in March, April, and May ; 



248 in June, July, and August ; 



259 in September, October, and ^November. 



273 per 1,000 of the deaths from all causes occur during 

 December, January, and February ; 



290 during March, April, and May ; 



222 during June, July, and August ; 



225 during September, October, and November. 



Whence it appears that the deaths from consumption are 

 during the summer 8 per cent, less than during the autumn, 

 4 per cent, less than during the winter, and 5 per cent, less 

 than during the spring. On the other hand the deaths from 

 all causes during the summer are 2 per cent, less than during 

 the autumn, 5 per cent, more than during the winter, and 6 per 

 cent, more than during the spring. So we conclude that the 

 summer weather, which is maleficial as regards disease in 

 general, causing an increased mortality of 5 per cent, over that 

 of winter, is beneficial — specially beneficial — in phthisis, 

 causing a lowered deathrate of 4 per cent. 



Can we explain to what this lower mortality in summer is 

 due ? Not altogether satisfactorily. May it be due to the 

 heat ? Probably to some — to a large extent. The fact that 

 the minimum deathrate occurs in summer points to an anta- 

 gonism between heat and phthisis. But heat will not wholly 



The mean monthly temperatures for the ten years 1865-74 are as follow, 

 "with the quarterly means : — 



Dec, Jan., Feb. Mar., April., May. June., July., Aug. Sept., Oct., Nov. 

 71-4 73-7 73-8 70-1 64-6 58-2 54-4 51-5 53-7 56-9 62-5 66-5 



218-9 ~19?9 159-6 ~~18IH) 



72-3 64-3 53.2 61.0 



The quarterly deathrates from phthisis are — 



208 ' 285 248 259 



