17 
toweling. None of the cultures were killed. Sulphur dioxid has 
always been regarded as merely a surface disinfectant against bacterial 
infection. The results of all who have tested the gas are unanimous in 
concluding that it has very feeble powers of penetration. Its effect 
upon mosquitoes is -in striking contrast to its bactericidal action in this 
regard. 
EXPERIMENTS WITH LIQUID SULPHUR DIOXID. 
No. 14. 
One tin can containing 20 ounces of liquid sulphur dioxid gas was 
opened in the room containing 500 cubic feet. The temperature in the 
room was 29.3° to 30° C. Exposure eighteen hours. One of these 
20-ounce cans is supposed to suffice for 1,728 cubic feet, so that the 
amount used was about three and a half times that required for bacterial 
disinfection. 
The mosquitoes and the cultures were exposed in the pill boxes with 
gauze lids, under similar conditions, as follows : 
In pill boxes: 
On floor, under carpet 
In canvas mail sack, folded 
In pocket, duck coat, hung up 
In pocket, cloth trousers, hung up 
Under 2 layers, dry toweling 
Under 2 layers, damp toweling 
Wrapped tightly in dry towel, 7 layers 
Wrapped tightly in damp towel, 7 layers 
In coat pocket, hung up, flap closed 
In bottom 12-inch beaker, covered with 2 layers toweling... 
In corner folded newspaper, under 7 layers 
Mosquitoes. ' 
Bacteria. 
Dead. 
Alive. 
Subtilis Pyocya- 
spores. neus. 
6 
i 
0 
-i- 1 — 
8 
0 
+ 1 - 
7 
0 
+ i - 
7 
0 
1 + — 
6 
0 
1 -h ' — 
5 
0 
1 -L : 
5 
0 
! + 1 ~ 
5 
0 
+ ! - 
4 
0 
+ , — 
6 
0 
1 + — 
7 
0 
1 
1 ! 
The moisture of the atmosphere during this test was determined by 
drawing the atmosphere over calcium chlorid. The gain in weight 
showed the presence of 0.2692 grams of moisture per liter. 
No. 15. 
A second test with the liquid sulphur dioxid was made. The con- 
ditions were precisely similar to those of the preceding experiment. 
No. 14, excepting that moisture in the form of steam was injected 
' through the keyhole after the gas was liberated. The temperature of 
the room during the exposure was 29.3° to 30° C. The atniosiihere 
was saturated with moisture. 
2 
