12 LAW OF DENSITY TO DEATH RATE. 



forty -three per thousand; and, sixthly, in the highest column, they 

 are aggregated together in the proportion of five hundred and 

 eighteen, with the death-rate of forty-five per thousand. The 

 fourth and fifth are only apparent exceptions to the rule of an 

 increasing death-rate with an increasing density of population. 

 The inhabitants of these districts, although fewer, are more 

 densely huddled together. 



Look now, for a moment, at the composition of each of these 

 columns, and you will observe that the death-rate from infectious 

 diseases, not only steadily increases with the density of its popu- 

 lation, but also that from pulmonary and " unclassified " diseases. 

 These groups are represented in different colours, and will assist 

 you to form a juster conception of the dangers resulting from 

 over-crowding. 



The credit of working out, and applying this important law of 

 death-rate to density, belongs to Dr Farr. 



Taking the five hundred and ninety-three registration districts 

 into which England and Wales (not including London) are divided, 

 he arranges them into so many groups according to their densities, 

 beginning with the most thinly populated rural district, with only 

 a hundred and sixty persons to the square mile, and ending with 

 the most densely packed town districts, as Glasgow and Liver- 

 pool, with over sixty thousand on each square mile. Let us now, 

 with the assistance of these other diagrams, note the results. 



In the district with 166 on each square mile there is a death-rate of 17 p. 1000 

 379 22 



1718 



4499 



12,357 (Manchester) 

 66,000 (Liverpool) 



25 



28 



Glasgow, with a density of population nearly similar to that of 

 Liverpool, has a much lower death-rate, thanks to the en- 

 lightened exertions of its able health officer. 



How comes it then, that persons living in thinly-peopled rural 

 districts (165 to the square mileX die annually in the proportion 



