Jan. 31, 1916 
Effects of Refrigeration on Trichinella spiralis 
827 
in No. 65. Four rats as cor ols were fed a total of 20 gm. of meat on 
July 8, 1915, from the ham which had been kept unfrozen since the 
slaughter of the hog—nearly eight months. No infections resulted. The 
trichinae had evidently died. Examination on August 25 of some of the 
meat after artificial digestion showed only a few trichinae. These were 
dead and disintegrated. There is little doubt, however, that if control 
animals had been fed early enough, they would have become infested, 
since trichinae from the unfrozen meat examined after artificial digestion 
as late as three weeks after slaughter of the hog were quite lively and 
appeared altogether normal. 
In experiments 77 to 87, meat from five trichinous hogs was used. 
Three 1 -pound cans (554 by 2% inches) were filled with meat from the 
first hog. One of the cans was placed in the center of a box 28 by 19 by 
6>^ inches, containing about 100 pounds of pork trimmings, and another 
in the center of a barrel of pork trimmings weighing 383 pounds net 
(dimensions of the barrel not recorded). Two cans were filled with 
meat from the second hog and two each in the case of the third, fourth, 
and fifth hogs, and one can of meat from each hog was placed in the 
center of a box of trimmings, as was done with one of the cans of meat 
from the first hog. A shoulder from each hog was kept unfrozen to 
provide material for control examinations. These shoulders were kept 
in a cooler or an ice box, except during the time when they were in 
transit between Chicago and the Washington laboratory. 
The five boxes and the barrel were placed in a refrigerated compartment 
or freezer, maintained at a temperature of — 2 0 to 5 0 F. The five loose cans 
were placed in a freezer maintained at 12 0 to 16 0 . The boxes were 
kept in the freezer for 15 days, the barrel for 23 days, and the loose cans 
for 17 days. During the time the meat was in the freezers the tempera¬ 
ture was recorded three times daily, using a thermometer which was after¬ 
wards compared with a standardized thermometer, and found to be sub¬ 
stantially correct. The temperature of the freezer in which the boxes 
and the barrel were kept varied from — 2 0 to 5 0 during the time the box and 
barrel containing meat from the first hog were in it. During the time the 
four other boxes were in this freezer the temperature varied from — 2°to2°, 
The temperature of the freezer in which the five loose cans were kept 
varied between 12 0 and 16 0 during the time the can of meat from the 
first hog was in it, and between 13 0 and 15 0 during the time the four other 
cans were in it. 
When the boxes were removed from the freezers after 15 days' exposure 
to cold, they were allowed to thaw slowly until the cans could be removed, 
which required two days (three days in one case, experiment 77). The 
thawing of the barrel required five days. After removal the cans were 
forwarded by mail from Chicago to Washington, where they were kept 
after arrival in an ice box or in a cooler (temperature, above 32 0 F.) until 
they could be examined. The time elapsing between removal from the 
