Aug. 15, 1919 



Effects of Heat on TrichincE 



211 



The results of other experiments with various lots of decapsuled lar\^ae 

 are shown in the followinsf table : 



Experiment 10. — A 0.6 per cent salt solution was heated to 56° C. 

 At this point some decapsuled larvae were spurted into the solution from 

 a capillary pipette. The temperature dropped from 56° to 55° in 75 

 seconds, and the contents of the vessel were then emptied into a shallow 

 dish and examined. Of 25 larvae, 14 were uncoiled and 1 1 tightly coiled. 

 The same experiment was repeated. Of 21 larvae, only 3 were com- 

 pletely uncoiled. In another test the larvae were spurted into the solu- 

 tion at 55° after which the temperature was allowed to drop to 54°, 

 which required 85 seconds. On examination following transfer to a shal- 

 low dish, only 3 out of 18 larvae were found to be completely uncoiled. 



In order to control the results of direct examination of decapsuled 

 larvae after heating, the junior writer in two instances fed some of the 

 larvae to rats. Thus larvae heated rapidly to 55° C. in Experiment 9 

 were fed to two rats, which when killed at the end of a month were found 

 to be moderately infected, a result in agreement with the results of direct 

 examination of the larvae. In another case — one of the experiments 

 summarized in Table I — larvae heated gradually for 60 minutes to 55° 

 were fed to two rats, which were found free from trichinae a month later. 

 Another rat fed unheated decapsuled larvae from the same source became 

 infected. 



From the foregoing experiments it is evident that decapsuled trichina 

 lar\^ae are killed by a temperature of 55° C, provided this temperature is 

 gradually attained. Many may be killed by lower temperatures, but the 

 results of heating to temperatures lower than 55° are uncertain. It is 

 also apparent that a momentary exposure to a temperature of 55° is not 

 sufficient to destroy the vitahty of decapsuled larvae, as is shown by the 

 results of Experiments 1, 9, and 10. 



