10 
Xo. 6. 
This experiment was done under the same conditions as the preceding. 
Six hundred cubic centimeters, or about 20 ounces of formalin, were 
again used in the Trenner-Lee formaldehyd disinfector. The exposure 
this time, however, was eighteen hours, and the mosquitoes and cultures 
were placed under precisely similar conditions, as follows : 
Mosquitoes. 
Bacteria. 
Dead. 
Alive. 
Garden 
earth. 
Subtilis 
spores. 
Anthrax 
sp< res. 
Pyoeya- 
neus. 
Staphy- 
loi occus. 
leter- 
oides. 
In battery jar with 
crumpled towel 
loosely filling half 
of it 
2 
1 
In pill boxes — 
Under 1 layer of 
newspaper 
o 
0 
- - - 


— 
In corner of 
newspaper, 
folded twice 
2 
0 
Under 2 lavers 
dry toweling.... 
Under 4 layers 
2 
0 
“T 
T 
— 
— 
— 
dry toweling ... 
W rapped tightly 
1 
0 
~T 
+ 
— 
in a small 
towel 
2 
1 
t 
In open pocket 
of coat, hung 
up 
2 
0 
, 
In open pocket 
of duck coat, 
hung up 
2 
0 
"T 
+ 




On the fioor un- 
der several 
towels 
1 
1 
These results are better than Xo. 5, in which the exposure was only 
six hours, the other conditions being similar. However, one of the 
mosquitoes escaped destruction in the battery jar, one tightly wrapped 
in a towel, and one on the floor under several towels laid loosely in a 
heap over the boxes containing the insects. These conditions might be 
found in actual practice, especially in bedrooms containing heaps of 
clothing, bedding, or other fabrics where the mosquitoes, according to 
our observations, could readily find a hiding place where they might 
escape the action of the formaldehyd. 
In this test the gas was in sufficient concentration to kill all the non- 
spore- bearing bacteria, excepting a staphylococcus under 4 layers of 
toweling. Some of the spores were also killed under conditions not 
requiring deep penetration. 
Xo. 7. 
In the third test with the Trenner-Lee formaldehyd disinfector a small 
room containing 250 cubic feet was used. This room is the same as the 
one described under Xo. 4. The single window was simply closed without 
pasting the cracks. Five ounces of formalin with 1 per cent of glycerin 
