Jan. 31,1916 
Effects of Refrigeration on Trichinella spiralis 
829 
1914, and was inclosed on January 17,1915, in three i-pound cans (5^ by 
2% inches), each can containing meat from all seven hogs. The shoulders 
after slaughter of the hogs were kept in a cooler at a temperature a few 
degrees above 32 0 F., except during the time when they were in transit 
between Chicago and Washington. Five of the seven hogs were the 
same as those from which the meat for experiments 77 to 87 was taken. 
On January 18 the three cans were placed in three freezers in New York 
City where they remained until February 1, a period of 14 days or, to be 
exact, 13 days, 23 hours. The temperature of the freezers as determined 
by thermometers compared with a standard thermometer during this 
period was 4 0 to 7 0 , 8° to ii°, and 14 0 to 16 0 F., respectively (four read¬ 
ings daily). After removal from the freezers the cans were allowed to 
thaw at ordinary temperatures and were received for examination at the 
Washington laboratory on February 4. 
The same routine as to the examination and feeding of experimental 
animals was followed as in the preceding experiments (77 to 87) except 
that the digesting fluid used contained only 5 gm. of sodium chlorid to 
each 1,000 c. c. of water, instead of 6 gm. In this case, as in the preceding 
set of experiments, no control animals were fed, but it happened that the 
test animals fed with the meat exposed to the temperature of 14 0 to 16 0 F. 
became infested, so that they served as a control upon those fed with meat 
exposed to the lower temperatures. 
In the series of experiments numbered 91 to 126, the meat used was 
taken from six hogs slaughtered in Chicago prior to March 2, 1915, and 
found to be trichinous on microscopic examination. A shoulder from 
each of these hogs was sent in the fresh condition to Washington where 
it was retained in a cooler slightly above 32 0 F. to provide material for 
control examinations and feedings. The meat for the freezing experi¬ 
ments was inclosed in thirty-six 1-pound tin cans (sH inches), 
some from each of the 6 hogs being placed in each can, so that each can 
contained a mixture of approximately equal portions of meat from all 
the hogs. On March 2, twelve of the cans were placed in a freezer 
maintained at a temperature of about 5 0 (5 0 to 6.5°), 12 in a freezer main¬ 
tained at a temperature of about io° (9 0 to 13 0 ), and 12 in a freezer 
maintained at a temperature of about 15 0 (13.5 to 15 0 ). After 10 days— 
on March 12—a can was removed from each of the 3 freezers and 
sent by mail to the Washington laboratory. The next day 3 more 
cans were removed as before, and so forth, the last cans being removed 
on March 25, after 23 days' exposure to cold. None was removed 
March 14 or 21, or 12 and 19 days, respectively, after they were placed 
in the freezers. The thermometers in these freezers, which were after¬ 
wards compared with a standardized thermometer, were read three 
times daily. 
The same routine examination was followed as in experiments 77 to 
90, described above, the formula of the digestant fluid being that used 
