13 



HOW FAE CAN THE GENERAL DEATH-EATE FOR 

 ALL AGES BE EELIED UPON AS A COM- 

 PARATIVE INDEX OF THE HEALTH OE 

 SANITAET CONDITION OF ANY COMMUNITY ? 



By E. M. Johnston, F.L.S. 



Indices to the state of healtli or sanitary condition of a 

 community are of the utmost importance to all, and 

 especially so to those who are responsible for local sanitary 

 provisions; and hence it is often asked, how far is the general 

 death-rate of any year to be relied upon as a test of either 

 the health or sanitary condition of any place or country ? 



I shall this evening try to demonstrate that the general 

 death-rate of any one place, though in itself due to a 

 combination of many complex causes, may, nevertheless, be 

 used as a fairly reliable local index to health and sanitary 

 condition, although a most faulty index as regards the 

 comparative health or the sanitary condition of different 

 localities. The dominant injEluences which determine the total 

 death-rate are these : — 



1. The proportions living at various age groujps, especially 



the old age group, 60 years and over, 



2. Migration, as affecting the said proportions. 



3. Birth-rate as affecting the death-rate of 0-5 years age 



group. 



4. Climate. 



5. Seasonal influence. 



6. Cosmical or obscure influences varying or intensifying 



local causes of disease over wide cycles of years. 



7. War, violence, and famine. 



8. Density of population as exemplified by town and 



country dwellings. 



9. Sanitary provisions. 



10. Local conditions of soil, altitude, etc. 



Now, of these important influences, which together combine 

 to make up the total death-rate, the first three, though 

 strongly affecting it, are not in the slightest degree connected 

 with either health or sanitary conditions. It is also obvious, 

 so far as any one locality is concerned, that many of the 

 conditions enumerated are more or less constant ; while, as 

 regards different localities, and especially countries widely 

 apart, nearly all the conditions come into play as disturbers, 

 and hence it is, that the general death-rate of any one locality 



