184 president's address — section I. 



them with natural or artificial asphalte puts them into the best 

 condition. It not only makes the surface that is mopt easily 

 cleaned, but its imperviousness prevents rain and house slops from 

 soaking into the soil, and carrying surface impurities that pollute 

 the ground air that finds its way into the neighboring house. 

 Much of the disease in the older colonial toAvns and villages is 

 caused by the fact that, for some generations, that part of the 

 sewage which is represented by household slops has been thrown 

 out of the back door, and that consequently the soil upon which the 

 house stands is sewage-sodden, and the ground air tainted. This 

 making of the back yard into the slop and refuse receptacle of the 

 houses causes probably the M'orst evils attending over-occupation of 

 the ground of towns. 



The influence of the density of the population of a given area on 

 the health of that population is well known. The precise condi- 

 tions under which arose the most flagrant instances of over- 

 crowding are not likely to recur on this side of the world ; but the 

 value of land in the larger cities is having the effect of encouraging 

 the building of many-storied houses. The greatest density of 

 po|)ulation that I have heard of occurred in the Cowgate, at 

 Edinburgh, with 900 people to the acre. An area in Dundee had 

 724 to the acre, with a yearly death rate of 58*4 in the thousand. 

 These were small areas; but in Glasgow there were x8 acres with 

 574 people to the acre. In these cities, and in Birmingham, 

 Liverpool, London, and other places, much has been done under 

 special Acts or under the Artizans' and Laborers' Dwellings Acts 

 in the way of clearing out these nests of disease, and with marked 

 effect on the health of the people. The death rate of the areas 

 dealt with in Birmingham fell from o3-2 in the thousand to 21 -3 ; 

 and in these colonies all of us who have to do with the conservation 

 of public health know places where wholesale demolition and re- 

 building are the only effectual remedies for the present unhealthy 

 condition of things. 



In connection with the prevention of over-density of population, 

 the establishment and keeping up of public parks and open spaces 

 is of great importance. The neglect of public authorities at home 

 to do this in the past has thrown a great burden on the present 

 generation. Let us, wherever there is time and opportimity, 

 follow the excellent example of the founders of the city we are 

 meeting in, when they reserved the belt of park lands. Such a 

 belt is to my mind better than the same area of land in one block 

 or park, just as securing wide tree-planted streets and boulevards 

 is better than the formation of extra urban parks. Have both if 

 possible, but begin with the streets. In nearly every city chances 

 continually occur, and are continually lost, of securing and planting 

 odd nooks and corners in the more thickly-peopled districts. 



When all the work thus far mentioned in connection with 

 securing the purity of the open air have been carried out, there 



