47 
Table 4. — Experiments with the autoclave. 
Number. 
Temperature of room 
before experiment. 
Time required to ex- 
haust autoclave. 
Time between begin- 
ning of discharge 
to drawing of air. 
Time required to 
draw air. 
Volume of air drawn, 
in liters. 
l 
Relative humidity 
before experiment. 
Relative humidity 5 
minutes after re- 
moving autoclave. 
Increase in grains of 
moisture per cubic 
foot. 
Abs. formaldehyde 
used per cubic foot. 
Abs. formaldehyde 
found per cubic foot. 
Per cent yield. 
Weather conditions. 
°F. 
m. 
gm. 
gm. 
I 
80 
25 
3 32 
1 18 
10 
75 
96 
2.96 
0.107 
0.0406 
37.94 
Almost no wind. 
II 
31.5 
25 
“0 35 
1 17 
10 
81 
94 
2.00 
.107 
0. 04213 
39.37 
Good breeze. 
&3 33 
1 4 
10 
.107 
0.0216 
20.18 
Storm. 
III 
80 
22 
a 40 
1 10 
11 
75 
94 
2.23 
.107 
0.04448 
41.57 
Almost no wind. 
61 41 
1 20 
11 
.107 
0.04116 
38.46 
Do. 
IV 
49 
25 
0 15 
1 7 
10 
67 
81 
.78 
.107 
0.1851 
17.30 
No wind. 
V 
41 
23 
0 15 
1 30 
10 
69 
92 
.77 
.107 
0.01471 
13.75 
Light breeze. 
From the result of III a it seems probable that on a warm calm day 
in a fairty tight room the amount of formaldehyde by the autoclave 
from 600 c. c. of formalin would be approximately 42 per cent after an 
interval of about 15 minutes from the time of removing the nozzle from 
the room. 
II a is lower than III a, which was to be expected, because of the 
strong wind. 
II b shows the rapid loss of formaldehyde gas during a strong 
wind or storm. During the time that the air was drawn in this experi- 
ment a severe windstorm was in progress, with the result that during 
the interval of 3 hours between a and b nearlj" half the formaldehyde 
escaped from the room. 
In these, as in the determinations in the case of the other methods 
of charging the room, the results represent the average quantity of 
formaldehyde for the interval during which the air was drawn. 
Even during warm weather (80° F.) apparently over half of the for- 
maldehyde gas in the 600 c. c. of formalin used to charge the room 
was lost. It is altogether improbable that the most of this escaped 
from the room during the 25 minutes required to exhaust the auto- 
clave, as is evident from the slow rate of loss on a calm day shown in 
I and III a and b. It is more probable that under the high tempera- 
ture and pressure in the autoclave the formaldehyde undergoes 
change. The effects of a reduced temperature upon formaldehyde 
liberated b} r this method were about the same as those observed in 
case of the other methods already described. The reduction m per- 
centage of formaldehyde obtained is shown in experiments IV, tem- 
perature 49° F., and V, temperature 41° F., which gave 17.30 percent 
and 13.75 per cent, respectively. 
Germicidal properties.— The method of procedure has been de- 
scribed, the organisms being exposed after all the formalin, etc., had 
been vaporized and injected. 
32507— No. 27-06- 
4 
