350 Miss E. Jolmstone and Prof. Thos. Carnelley. [Feb. 14, 



The above results show : 



(1.) That the quality of the deafening, as indicated by the per- 

 centage of chlorine, nitrogenous organic matter, and combustible 

 matter, runs strictly parallel with the class of house, being by 

 far the worst in the one-roomed houses, and the best in the 

 largest houses. 



(2.) That the deafening employed in ordinary middle-class houses 

 is in almost all cases practically free from nitrogenous organic 

 matter and chlorides, and from any disagreeable smell, so that 

 110 objection can be raised to the use of deafening of the 

 quality we have examined in this class of house. 



(3.) In the poorer class of houses (of three rooms and under) 

 nitrogenous organic matter and chlorides are always present, 

 the percentage being especially high in the older houses, while 

 in many cases the smell is very objectionable. From this it 

 would appear that the air in such houses may be very seriously 

 polluted by the deafening, and thus give rise to ill-health. 



In reference to the above results we may remark : (1.) That the 

 cinders, which form the bulk of the deafening used in better class 

 houses are probably of good quality, owing to their being obtained 

 from a lion- contaminated source, whereas in the poorer class of houses 

 inferior materials (and possibly ash-pit refuse, &c.) will doubtless be 

 made to serve for filling up the deafening space. (2.) The carpets in the 

 better class of houses are not usually lifted oftener than twice a year, 

 and of course the floors can only be washed at those times, so that the 

 necessary condition of moisture for the growth of micro-organisms is 

 not present to the same extent as in lower-class houses, while at the 

 same time the carpet will act as a partial filter to micro-organisms 

 arising from the deafening material. In the poorer class of houses, 

 however, everything would seem to favour the contamination of the 

 air from this source. The floor boards are often plain jointed, and 

 simply laid side by side, so that when the floor is washed the water 

 has every facility for trickling down to the material beneath. 

 Further, all the household operations of washing, cooking, nursing, 

 &c., have to be carried out in the one or two apartments, and hence 

 the spilling of dirty water, slops, &c., on the floor, and percolation 

 into the deafening below will be of pretty frequent occurrence. The 

 rooms are often overcrowded, and consequently the air is moist and 

 warm, so that the increase and multiplication of micro-organisms 

 would seem to be inevitable. 



It has been shown (Carnelley, Haldane, and Anderson, ' Phil. 

 Trans.,' B. (1887), p. 61) that in passing from many to two- and one- 

 rooined houses the air becomes more and more impure, especially with 

 regard to the number of micro-organisms, whilst the death-rate 



