110 
PROF. T. CARNELLEY, MR. J. S. HALDANE, AND DR. A. M. ANDERSON 
quarters of a square yard of ground to each person. It is, in fact, the largest and 
closest-packed block in Dundee. Formerly the ventilation was veiy had, hut by 
order of the sanitary authorities one room on each flat was thrown open as an air 
space, and the glass removed from the windows and replaced by open wire grating. 
The average temperature in this block was 54°, or only 1° below the average of all 
the one-roomed houses we examined, although the outside air at the time was 5° 
lower on the average than on the nights when the other one-roomed houses were 
examined. The analytical results obtained were as follows :— 
Block of buildings referred to. 
General average 
of 1-roomed 
houses. 
House on 
House on 
House on 
House on 
4th flat. 
3rd flat. 
3rd flat. 
2nd flat. 
Space per person .... 
212 cubic feet 
193 
169 
193 
225 
Temperature. 
55° Fabr. 
, . 
52 
53 
56 
Carbonic acicl. 
11-2 
8-6 
7-9 
8-8 
io-o 
Organic matter (excess) . 
6-7 
4-0 
3-8 
3-0 
33 
Total micro-organisms 
60 
21 
95 
45 
53 
From this it will be seen that the open-air spaces have a marked effect in improving 
the condition of the air in such houses as those referred to. Since this alteration has 
been made a very marked improvement has taken place in the health of the inhabi¬ 
tants of this block of buildings. 
(3.) The practice adopted in almost all small houses of keeping a lamp burning 
during the night is one to be deprecated, as it must add very considerably to the 
contamination of the air, especially in one-roomed houses, in which the cubic space 
per person is so small. 
(4.) Cleanliness, both of the person, and more particularly of the dwelling or 
school, is of the very utmost importance in maintaining the purity of the air as 
regards micro-organisms, and one which from this point of view has not been pre¬ 
viously advocated. 
(5.) Though far from depreciating the beneficial effect of abundant air space, yet 
we think that the frequency with which the air in a room is changed is a far more 
important point to be attended to in providing a pure atmosphere. 
(6.) Ventilation by mere diffusion should never be depended on alone, for, though 
it may remove a considerable portion of the carbonic acid, it has, probably, but little 
effect in reducing the organic matter and micro-organisms. 
(7.) It is most important that the windows in houses and schools should be made 
to open widely, so that at intervals a good current of air may be sent through the 
room. This would be very effective in removing the organic matter and micro¬ 
organisms. 
In conclusion, we have to express our best thanks to Miss Etta Johnstone, of 
