848 
Journal of Agricultural Research 
Vol. V, No. 18 
their vitality so that many were found to be inactive which before diges¬ 
tion were still alive, the results of the examinations corresponded very 
well with the feeding tests. In fact, the examinations not uncommonly 
showed some of the trichinae to be still alive, whereas in the corresponding 
feeding tests with the same meat not artificially digested none of the test 
animals became infested. On the other hand, there was no case in the 
freezing experiments in which the feeding test resulted in infection and 
the corresponding examination failed to reveal living trichinae unless 
experiment 86 be taken as an exception. In this experiment, following 
a negative examination of digested meat, 3 larval trichinae were found in 
the intestine of one of the test rats, which died four days after the first 
feeding; one of these larvae was alive and exhibited feeble movements, 
but none of the 3 had undergone any development; the 4 other test rats 
failed to become infested. Experiment 67 was nearly an exception to 
the rule, as only 2 live trichinae were found among 285 examined, the 
feeding test resulting positively. Only one out of four test rats became 
infested, however, and this one had but 3 trichinae in the diaphragm. 
On the whole, the method of artificial digestion appears to afford a more 
rigorous test of the viability of trichinae than the feeding of experimental 
animals in view of the fact that trichinae are often found to be alive in 
digested meat when the feeding of the undigested meat to experimental 
animals fails to produce infection. 
As a rule, in testing meat it is preferable not to depend alone upon the 
results of artificial digestion or the results of feeding test animals, but to 
employ both methods and take the results of both into consideration. 
It is quite evident from the results of the experiments that artificial 
digestion is a valuable method for testing the viability of trichinae, and 
that when properly controlled its injurious effects upon their vitality are 
so slight as to be practically negligible. The following formula may be 
recommended as fully satisfactory: 
Water. 1,000 c. c. 
Hydrochloric acid (sp. gr. 1.19). xo c. c. 
Scale pepsin (U. S. P.).2.5 gm. 
Sodium chlorid.. 5 gm. 
Fifty grams of ground meat are to be stirred into 600 c. c. of the 
digesting fluid, warmed to 38° or 40° C., and incubated for about 18 
hours at this temperature. 
LONGEVITY OP TRICHINAE AFTER ARTIFICIAL DIGESTION 
Trichinae freed from their capsules by artificial digestion have been 
kept alive in tap water for 15 days. In one case 73 out of 75 were active 
at the end of this time. When examined again, 13 days later, all were 
dead. Kept in a 0.6 per cent sodium-chlorid solution for 16 days, 41 out 
of 43 examined were alive, some of them being sluggish but most of them 
