i 
neus. These 3 series were exposed side by side under the conditions as 
noted in the following table : 
IMosquitoes. 
Bacteria. 
Dead. 
Alive. 
Subtilis 
spores. 
Pymcy’a- 
neus. 
In pill boxes; 
In pocket of duck coat hung: on wall, pocket toward wall.. 
% 
3 
1 
Same as above, except pocket open and turned out 
5 
0 
+ 
— 
Under 2 layers of damp toweling 
5 
7 
[ -|- 
— 
Under 2 layers of dry toweling 
4 
0 
— 
In pocket of overalls hung on wall, pocket closed and 
hung against the wall 
1 
4 
-1- 
Control ; exposed to the gas without protection 
4 
0 
— 
It is perfectly plain from this experiment that the mosquitoes exposed 
freely to the action of formaldehyd are killed. They are, however, able 
to survive an exposure to less concentrated atmospheres of the gas. 
They lived in the pocket of a coat and overalls, and under a few layers 
of toweling, despite the fact that the gas penetrated to these places in 
sufihcient strength to kill pyocyaneus and sometimes dry subtilis spores, 
lying right alongside of the insects, and exposed to precisely similar 
conditions. 
The conclusion is evident, therefore, that in rooms where the mos- 
quitoes may have similar places to hide, this method is not available. 
THE KUHN LAMP. 
This lamp operates upon the principle of dehydrating methyl alcohol 
into formic aldehyd. The vapor of the alcohol is passed over incan- 
descent platinum in a state of fine division upon perforated asbestos 
discs. In practical disinfection against bacteria, 20 ounces of wood 
alcohol are prescribed for each 1,000 cubic feet of air space, the 
exposure to be not less than six hours. 
No. 3. 
In the room of 2,000 cubic feet capacity described in experiment No. 
1, 40 ounces of wood alcohol were consumed in a Kuhn lamp. The 
time of exposure was twenty-four hours. Temperature 81° to 87° F. The 
mosquitoes and the slips containing the cultures were in similar boxes, 
and exposed side by side to the same conditions, as follows : 
Mosquitoes. 
Bacteria. 
Dead. 
Alive. 
Subtilis 
spores. 
Pyocya- 
neus. 
In pill boxes : 
Under 1 layer damp toweling 
1 
2 
+ 
Under 2 lay’ers damp toweling 
1 
2 ' 
+ 
— 
Under 4 layers damp toweling 
4 
0 
+ 
— 
Under 4 layers dry toweling 
2 
1 
+ 
Lost. 
Wrapped in dry towel, 4 layers 
5 
0 
+ 
— 
W’ rapped in damp towel, 4 layer.s 
4 
0 
-f- 
-b 
In overalls pocket (damp), hung up, pocket toward wall... 
0 
4 
-b 
— 
In overall (dry), hung up, pocket turned out 
0 
4 ' 
+ 
— 
In canvas mail sack, mouth tied 
0 
4 
+ 
— a 
Under pile of loose clothes 
1 
3 
-f- 
-b 
Control, in air-tight jar, dry' 
0 
3 
+ 
-b 
Control, in air-tight jar, with moisture 
2 
1 
-b 
+ 
a Contaminated. 
