838 
Journal of Agricultural Research 
Vol. V, No. iS 
In 38 experiments test animals were fed meat which had been exposed 
to about 15 0 F. for periods ranging from 5 to 24 days, with positive 
results—i. e., resultant infection—in 17 experiments and negative results 
in 21. 
Some of the negative results were obtained in experiments in which 
the meat had been kept in the freezer for only 5 and 6 days; on the 
other hand, positive results were obtained from feeding meat which had 
been in the freezer for 23 days. Heavy infections were obtained from 
meat exposed as long as 18 days (experiment 122), but only slight infec¬ 
tions resulted from meat kept in the freezer for 20 days or longer (seven 
, experiments), and then only in two instances: In experiment 123 (20 
days) one rat was negative, four slightly infested, and in experiment 126 
(23 days) two rats were negative, three slightly infested. 
From these results it appears that trichinous meat commonly fails to 
produce infection after exposure to temperatures of about 15 0 F. for 
periods of 5 to 24 days, notwithstanding the fact that many trichinae 
remain alive and are quite lively when thawed out after such exposure. 
Failure to infect is probably because, first, of a reduction in the num¬ 
ber of live trichinae and, second, of a reduction in the vitality of those 
that remain alive. It may be concluded that although a temperature 
of 15 0 F. has an injurious action upon the vitality of trichinae, this tem¬ 
perature is uncertain in its effects and that meat exposed to a tempera¬ 
ture of 15 0 F. for as long as 23 days is still liable to produce infection. 
These results correspond to those obtained by Schmidt, Ponomarer, and 
Savelier (1915) who concluded from their experiments that a tempera¬ 
ture of — 9 0 C. (+15.8° F.) is sometimes fatal to trichinae, but not always 
and that the results of exposure to this temperature are variable and 
uncertain. 
The same authors also found that a temperature of — 6° (+ 21.2° F.) has 
comparatively little effect upon trichinae exposed to it for a period of 
10 days. 
Trichinae were found to be alive upon examination in 34 out of 35 
experiments in which trichinous meat was exposed to temperatures of 
about io° F. for periods varying between 30 minutes and 57 days, all 
but one of the experiments having to do with periods of 5 to 23 days. 
In the one case in which all of the trichinae were found to be dead (exper¬ 
iment 38) the meat had been artificially digested for 2 days in prepara¬ 
tion for examination instead of less than 24 hours as usual, which is 
the probable explanation why none was found alive. Although there 
-were no striking differences in the percentages of trichinae found alive 
as compared with the findings in the experiments in which meat was 
exposed to temperatures of about 15 0 , it was frequently noted that 
they were less lively than normal, commonly sluggish. In 20 of the 
experiments a record was made of the degree of activity and it was noted 
that in 19 of these the trichinae were sluggish, or at least less lively than 
