Makxcg# 1, 1901.] 
test, and how rapidly the farmer and 
middle-man could greatly improve the 
bacterial purity of their milk if only their 
dense ignorance and lack of desire to im- 
_ prove could be removed. 
Duration of Life of Typhoid Bacilli, derived 
from Twenty Different Sources, in Ice; Ef- 
fect of Intense Cold on Bacteria: W. H. 
Park, New York. 
Cultures derived from twenty different 
cases of typhoid fever were grown 28 hours 
in nutrient agar. From each one a loopful 
was inoculated into 300 cc. of sterile dis- 
tilled water and this was poured into thirty 
glass tubes. These were kept in a room 
averaging 23° F. (—5° C.). From time to 
time a tube was removed and the number 
of bacilli which should develop in nutrient 
agar tested. The following table gives the 
results: 
Per cent. of 
cultures living. 
Per cent. ot 
bacilli living. 
Number of 
weeks frozen. 
0 (Original) 100 20 
4 week 42 20 
* 1 week 14 20 
2 weeks 7.50 20 
eG 4 20 
st oll 18 
eae .09 18 
Geiss -05 17 
QM ts .005 11 
i) 9° -002 8 
1s ‘* -0004 3 
OO Tnine none 0 
Watery suspensions of typhoid, colon 
diphtheria and hay bacilli and of the Staphy- 
lococcus pyogenes aureus were placed in small 
tubes and dropped into liquid air. From 
time to time the tubes were removed and 
the contents plated in nutrient agar. The 
percentage living was as follows : 
Per cent. living 
after Typhoid.| Colon. | Staph. |B. sublitis. 
exposure of 
3 min. 18 19 
a) Oe 10 11 85 80 
60‘ 7.5 8 51 67 
io el aes ln vee 55 
SCIENCE. 
323 
The virulence of the organisms was only 
slightly diminished by this intense cold for 
two hours. 
The Use of Paraffin to exclude Oxygen in 
growing Anaérobic Bacteria: W.H. Park. 
Nutrient glucose bouillon in tubes or 
flasks covered with a layer of paraffin, 
melting at 42° C., has proved very useful in 
the devolopment of tetanus cultures and 
toxins and of other anaérobic bacteria. With 
bacteria not possessing spores the medium is 
quickly cooled and inoculated and then 
covered by a layer of very hot sterile par- 
affin. The accumulation of gas forces the 
paraffin up in the tube or flask, but does not 
allow the entrance of oxygen. When abso- 
lute exclusion of oxygen is desired, the tubes 
with their layer of paraffin are sterilized in 
an autoclave which renders them free from 
oxygen. Spore-bearing bacteria are inocu- 
lated through the liquid paraffin before the 
bouillon is fully cooled. Bacteria without 
spores are inoculated by breaking through 
the paraffin film or by heating the paraffin 
in a gas flame. A pipette can then be car- 
ried through the hot paraffin into the cool 
liquid below. The paraffin layer has also 
been found useful in preserving media from 
drying or from changes due to the absorp- 
tion of gases of the air. 
Bacteria in the Ames Sewage Disposal Plant: 
L. H. Pammet, Ames, Lowa. 
The author describes a sewage plant de- 
signed for the disposal of the sewage of 
about six hundred people. The plant is of 
the ordinary type, consisting of two beds, 
each covering about 0.2 of anacre. The 
filtration in the beds was at the rate of 
about 100 gallons a day, per acre. The 
whole plant was installed for about $3,000. 
The efficiency of the filter bed was shown 
by bacteriological analysis. The effluent 
of the filter bed for 1899 showed an average 
of 5,127 bacteria per cubic centimeter, and 
at no time did it rise over 11,075 per ce. 
