23^ DUST AND WATER. 



those having charge of sanitary supervision, which its 

 presence suggests, and that is contamination of the air 

 we breathe by the liberation of posionous dust particles 

 from various hangings, and other decorative articles 

 vrhich are freely used to beautify our homes. Many 

 cases of serious illness have been traced to the posionous 

 coloring matter used in certain v^all papers, and I have 

 no doubt the dyes used in many tapestries, hangings and 

 other articles of upholstery, so common in domestic use, 

 are responsible for many more. 



Of course the quantity of dust in the air, whether out 

 of doors or in our houses and places of assembly, differs 

 very much according to different conditions. While 

 there is always a certain quantity of suspended matter 

 in the air, the general tendency of dust is to settle. 

 Hence disturbance by atmospheric currents, or mechani- 

 cal means, always increases the amount which we are 

 forced to inhale wherever we may be. Careful investi- 

 gation has shown that under ordinary conditions the 

 dust laden air, in the streets of a city, on a moderately 

 breezy day, contains far more living germs to the cubic 

 inch than the air within what we would designate a well 

 kept dwelling. In April, 1890, a biological examination 

 of the dust, which was allowed to settle upon the bottom 

 of a round dish 3| in diameter, at several localities in the 

 City of New York, exhibited the following startling 

 result : 



At Central Park, 499. Ball ground. 



Union Square, edge of fountain basin, 214. 



Library of private house near 34th street and Broad- 

 way, 34. 



Large retail dry good store, 199. 



Railing of small park, Broadway and 35th street, 941. 



Cross street, through which carts of sweeping depart- 

 ment were passing, collecting dry heaps of street dirt, 

 5,810. 



192 



