Aug. IS. 1919 Effects of Heat on TrichincE 217 



trichinae may be destroyed by continued heating at temperatures lower 

 than that which kills on brief exposure. Like the experiments with 

 the decapsuled larvae, however, they are not sufificiently extensive to 

 allow definite conclusions to be drawn as to the periods of time necessary 

 to insure the destruction of trichinae exposed to temperatures lower than 

 the thermal death point. 



Experiment 24 (April 7, 191 3). —A small piece of the diaphragm of 

 the same rat which supplied the meat used in Experiment 14 was tied 

 in a cloth around the bulb of a thermometer, which was immersed in a 

 beaker of water heated to about 50° C. and the entire apparatus placed 

 in a constant-temperature oven. The temperature, as indicated by the 

 thermometer, varied from 50.2° to 51.6° during the two hours of heating 

 the meat. Larvae isolated from the meat by dissection were dead. 



Experiment 25 (April 9, 191 3). — Two small pieces of meat from the 

 same rat used in Experiments 14 and 24 were tied in cloths around the 

 bulbs of two thermometers and heated in a beaker of water as in Experi- 

 ment 24. During the experiment the temperature, as indicated by the 

 thermometers, varied between 49.6° and 50° C. One piece was removed 

 after an hour's exposure. Tvv^o larvae isolated from the meat by dissec- 

 tion were alive, but rather sluggish. The other piece was removed after 

 an exposure of i^ hours. Two larvae were examined, one of which 

 was dead, the other alive, but rather sluggish. Two guinea pigs were 

 fed with the meat, but neither became infected. Another piece of meat 

 from the same rat was similarly heated for one hour at a temperature of 

 50.1° to 50.4° C. A larva isolated from the meat after heating was alive 

 and active. Another piece was similarly heated for i}^ hours at 50°. 

 Five larvae were isolated from the meat and examined. Four were cer- 

 tainly dead, the other inactive, but with protoplasm less changed than 

 that of the others. 



Experiment 26 (August 31, 191 4). — Finely chopped meat from a 

 trichinous rat was placed in water in a flask, which was kept 2 1 hours in 

 an oven maintained at a temperature of 49° to 52° C. The temperature 

 of the water during this time varied from 48.8° to 51.4°. Four larvae 

 dissected out of the meat after heating were dead. The meat was fed 

 to two rats, both of which remained free from trichinae. Some finely 

 chopped meat from the same rat was heated 2 1 hours in a covered Petri 

 dish in the same oven at a temperature of 49° to 52°. Five larvae dis- 

 sected out of the meat after heating were dead. Two rats to which the 

 meat was fed remained free from infection. 



Experiment 27 (September 3, 191 4). — Finely chopped meat from a 

 trichinous hog was heated in a closed jar in a constant -temperature oven 

 for 19 hours. The temperature of the meat during this time varied 

 between 47.8° and 48.4° C. Twenty-five trichinae were dissected out of 

 the meat after heating and all found to be dead. 



