92 
EXPERIMENT NO. 54. 
Formalin, 2,000 c. c., permanganate, 1,000 grams, equally distributed in four galvanized-iron 
buckets, two of which were placed in the main sleeping compartment of car and one in the 
alleyway at each end. 
Weather: Very cloudy, some melting snow on ground, no wind. 
Temperature in car at beginning of experiment, 46° F. 
Relative humidity in car at beginning of experiment, 45 per cent. 
Time of exposure, 2 hours (11.25 a. m. to 1.25 p. m.). 
Temperature in car after opening and airing 15 minutes, 47° F. 
Relative humidity in car after opening and airing 15 minutes, 46 per cent. 
[4- means growth; — no growth.] 
Organism. 
Place of exposure in car. 
Result. 
B. coli communis 
Toilet room 
+ 
Drawing-room 
+ 
Floor main sleeping compartment 
4- 
Berth, upper No. 4 
+ 
Berth, lower No. 8 
4- 
B. diphtherise 
Floor main sleeping compartment . 
4- 
Berth, upper No. 10 
4 
Berth, lower No. 6 
+ 
B. yp osus 
Toilet room 
+ 
Drawing-room 
+ 
Floor main sleeping compartment 
4- 
Berth, upper No. 6 
4- 
Berth, lower No. 4 
+ 
B. subtilis 
D ra wing-room 
4- 
Floor main sleeping compartment 
4- 
Berth, upper No. 6 
'.4- 
As a rule, in this climate the relative humidity is higher at night 
than during the day, the reasons for which are obvious. The follow- 
ing three experiments were therefore done at nighttime of particu- 
larly dry days, and, as will be seen, gave better germicidal results 
than would have been obtained during the daytime. 
To show this difference in humidity, the official relative humidity 
at 2 p. m. of the day on which these experiments were done is there- 
fore given in each experiment. 
This matter is of practical importance in comparatively dry cli- 
mates, and shows the advantage of doing the work at nighttime. 
Of course still better results would be obtained by continuing the ex- 
periments until the next morning. However, the same results would 
not be obtained by starting the experiments during the day with a low 
humidity and continuing during the night, as much of the formalde- 
hyde would be lost before the humidity was raised; and, furthermore, 
the car being closed, practically the only change in humidity in the 
car would be as a result of the fall in temperature during the night. 
