Jan. 31,1916 
Effects of Refrigeration on Trichinella sfiralis 
839 
normal, and that in the twentieth they were nearly all very lively (experi¬ 
ment 11,6 days’ exposure). It was quite noticeable in the examinations 
that the activity of the trichinae was generally much more impaired than 
in the case of meat exposed to 15 0 . 
In 41 out of the total of 43 experiments in which meat was exposed to 
temperatures of about io° F., test animals were fed, the results being 
positive in 22 cases, negative in 19. In one of the latter (experiment 
73) one out of five rats was found to be heavily infested, but there is 
a question as to the identity of this rat; furthermore, the trichinae were 
too far advanced in development to have resulted from meat fed at the 
time the rats belonging to this lot were fed. In feedings with meat 
exposed to temperatures of about io° for 13 days or less, heavy infesta¬ 
tions were commonly produced, but in 17 experiments with meat exposed 
14 to 23 days and in one with meat exposed 57 days the results of 
feeding were either negative or, if infection was produced, it was slight. 
In only 4 of these 18 experiments did any of the test animals become 
infested. In experiment 106 (14 days) three rats were slightly infested, 
two negative; in experiment 71 (17 days) one was very slightly infested 
(four trichinae in diaphragm), two negative; in experiment 65 (19 days) 
four were very slightly infested, one negative; and in experiment 65a (19 
days) two were very slightly infested (four trichinae in the diaphragm of 
each), two negative. 
Summarizing the results of the experiments with meat exposed to 
temperatures of about io° F. it may be noted that trichinae have been 
found to survive in meat exposed for as long as 57 days, though in that 
case only a small percentage, and those only sluggishly active, and that 
some survived in nearly all cases, their numbers and vitality, however, 
having been so reduced that after 14 days’ exposure either no infection 
resulted in test animals or, if infection resulted, it was very slight. 
Evidently, therefore, the effects of a temperature of io° upon the vitality 
of trichinae are decidedly more pronounced than those of a temperature 
of 15 0 . 
Twenty-five experiments were carried out in which trichinous meat 
was exposed to temperatures of about 5 0 F.; and in 23 of these, exami¬ 
nations were made of the trichinae after thawing. In only six instances 
were live trichinae found. In experiment 42 (5 0 to 7 0 for 5 days) 14 
per cent of the trichinae were found to be alive, degree of activity not 
recorded. The number of live trichinae found in the five other experi¬ 
ments ranged from less than 1 per cent to 3 per cent, and they were all 
very sluggish (experiments 44, 46, 88, 94, 98), the periods of exposure 
to cold being 7, 9, 14, 14, and 18 days, respectively. 
Test animals were fed in 23 experiments. No infections resulted 
except in experiment 42, just referred to. In this experiment three 
rats were fed and two became moderately and one slightly infested. 
