70 
PROF. T. CARNELLEy, MR. J. S. HALDANE, AND DR. A. M. ANDERSON 
received, and willingly allowed to collect the necessary samples of air, measure the 
room, and obtain such information as was required. We were, in fact, agreeably 
surprised to find that so little objection was made to our untimely visit. The precau¬ 
tion was, of course, taken of having the door open for as short a time as possible, and 
of avoiding unnecessary movements such as were likely to stir up dust and contami¬ 
nate the air. In the case of one-roomed houses the samples were taken about the 
centre of the room. In two-roomed houses we found that the door was always kept 
open between the two rooms, and that usually there were people sleeping in both 
rooms. We therefore in those cases took the samples by the door communicating 
between the two rooms. About ten minutes in each room were, as a rule, required in 
order to take the specimens, measure the room, &c., and about twenty minutes subse¬ 
quently for determining the carbonic acid and organic matter in the van. Half-an- 
hour in all was, therefore, required for each house. We could thus visit five or six 
houses each night, besides taking and analysing samples of outside air in the courts 
or lanes in which the houses were situated. 
In the case of houses of four rooms and upwards, houses of various sizes and in 
different parts of the town were selected, and were usually those of acquaintances. 
With one exception, we always found the windows and doors closed in the houses we 
visited. The rooms were examined in their usual conditions in every respect. 
One-roomed houses. 
Two-roomed houses. 
Houses of four rooms and 
upwards. 
No. of 
cases. 
Lowest. 
Highest. 
Average. 
No. of 
cases. 
Lowest. 
Highest. 
Average. 
No. of 
cases. 
Lowest. 
Highest. 
Average. 
Persons per house 
(per room in last 
class) .... 
29 
2 
10 
6*6 
13 
4 
10 
C-8 
18 
1 
3 
1-3 
Space per person 
29 
104 
528 
212 
13 
148 
395 
249 
18 
391 
4206 
1833 
Temperature(°F.) 
21 
43 
61 
55 
9 
50 
69 
53-5 
13 
42 
63 
54-5 
Carbonic acid. . 
29 
6’3 
32-1 
11-2 
12 
7-1 
13-2 
9'9 
18 
4*o 
11-7 
7*7 
Organic matter . 
29 
7'8 
38-1 
15-7 
11 
5-0 
30-2 
10-1 
18 
i-i 
12-0 
4-5 
Total micro- 
organisms :— 
28 
e-o 
240-0 
60-0 
13 
8-0 
128-0 
46-0 
18 
0-5 
22-0 
9-0 
Bacteria . . 
19 
6-0 
120-0 
58'0 
11 
6-0 
118-0 
43-0 
16 
0-5 
16-0 
8*5 
Moulds . . . 
19 
0 
5-0 
1-2 
11 
0 
10-0 
2-2 
16 
0 
1-0 
0-4 
The results shown in the above Table come out even more strikingly if, instead of 
giving the average total quantity of carbonic acid and organic matter, we give the 
quantities present in excess of the outside air at the time. This is done in the 
following Table. As the number of micro-organisms in the outside air was so small, 
they may be neglected, and therefore no change as regards micro-organisms is needed. 
