Jan. 3x, 1916 
Effects of Refrigeration on Trichinella spiralis 
849 
moderately lively. In another lot kept in a 0.6 per cent sodium-chlorid 
solution for 26 days, 15 out of 24 were alive and moderately active when 
warmed. Examined again 24 days later, all were dead. In a lot kept 
in 2 per cent sodium-chlorid solution for 11 days, 37 out of 38 were alive 
and very active. In these instances, after digestion of the meat, the 
trichinae were washed in several changes of water or in physiological salt 
solution by decanting and settling. They were kept at ordinary room 
temperature. Numerous observations were made which showed that 
trichinae freed from their capsules by artificial digestion will be apparently 
just as lively after several days if kept in water or physiological salt 
solution at ordinary room temperature as they are immediately after 
digestion. 
If tap water containing trichinae is kept at a temperature of 38° C. 
most of them are killed in a short time, but trichinae may be kept an 
equal length of time at this temperature in a 0.6 per cent sodium-chlorid 
solution without apparent injury as shown by the following: Trichinae 
from artificially digested meat were separated into two lots in beakers, 
one containing tap water, the other a 0.6 per cent sodium-chlorid solution. 
The two beakers were heated to 38° C. and this temperature maintained 
for hours. At the end of this time 23 out of 32 trichinae from the tap 
water were inactive, whereas 18 examined from the salt solution were all 
active. The two beakers after replacing the tap water in one with a 
0.6 per cent sodium-chlorid solution were kept at room temperature until 
the following day and then reexamined. Out of 108 trichinae examined 
in the one case (heated in tap water), 81 were found to be inactive, 
whereas in the other case (heated in salt solution) all but 1 out of 100 
examined were active. 
On another occasion some trichinae in tap water were kept at a tem¬ 
perature of 32 0 C. for about half an hour. Most of them became inactive 
but resumed their activity when the water was replaced with a 0.6 per 
cent sodium-chlorid solution, although their color became darker than 
normal and vacuoles appeared in the lateral fields. 
It was on account of this discovery of the injurious effects of warm 
tap water that in the later experiments when meat was digested artifi¬ 
cially it was washed with salt solution instead of tap water, and that 
salt solution instead of tap water w^as used as an examination medium. 
The use of tap water in the earlier experiments, however, probably 
affected the results of the examinations little, if any, as they are evi¬ 
dently quite consistent with the results of the later experiments (see 
Tables I and II). The washing was done with cold tap water, and in 
examining the trichinae they were transferred a few at a time to a warm 
stage, where they were kept only a few minutes, too short a period for 
the injurious effects of immersion in warm water to become established, 
as was repeatedly demonstrated in using this method upon trichinae 
from unfrozen meat. 
