DENSITY OF POPULATION AND DEATH RATE. 1 1 



at an expenditure equal to several pounds' weight per day ; but 

 during the febrile state health limits are vastly exceeded. 



I leave you to draw your own conclusions as to the consequences 

 which must follow to others, when this enormous amount of 

 infective material is daily set adrift for we must remember that 

 our waste and effete materials, under these conditions, become 

 charged with the virus of the disease ! 



I wish now to say a few words on what has been fittingly 

 named 



THE BREEDING PLACES OF INFECTIOUS DISEASES. 



For this purpose I select some of those localities from which 

 these diseases are never altogether absent, and from which they 

 usually go forth upon the rest of the community. Examine with 

 me for a little these diagrams : Of these six columns, the shortest 

 represents the healthiest district, the tallest the unhealthiest, 

 showing the extreme of six districts existing in different parts of 

 a neighbouring city. The upper portion of each column represents 

 the number of deaths from the infectious diseases which occur 

 in each of these districts ; the middle portion, the number of 

 deaths resulting from pulmonary diseases, mostly consumptive ; 

 the lower portion, the deaths from what is called " unclassified " 

 diseases. Now, notice that the rate of deaths steadily increases; 

 thus, in the district represented by the shortest column, the in- 

 habitants are aggregated together in the proportion of thirty-five 

 persons to every acre of it, and its death-rate is nineteen persons 

 per thousand annually. In the next they are aggregated together 

 in the proportion of four hundred and twenty-six persons to every 

 acre ; and its death-rate is thirty-five persons per thousand 

 annually. In the third, their aggregation is in the proportion of 

 four hundred and fifty per acre, with a death-rate of thirty-eight 

 per thousand. The fourth, the proportion is three hundred and 

 fifty per acre, and the death-rate forty-one per thousand. The 

 fifth is, three hundred and fifteen per acre, and a death-rate of 



