Aug. 15, I9I9 Effects of Heat on TrichincE 213 



heated to 53° was killed five weeks after feeding and was free from 

 parasites. The meat heated to 55° also failed to infect two guinea pigs. 



Experiment 13 (April i, 191 3). — Small pieces of meat from a trichi- 

 nous rat were heated as in the previous experiment; but an open flame 

 was used instead of an oven and the temperature was allowed to go up 

 very rapidly, the water in the beaker meanwhile being stirred con- 

 stantly. Meat heated from 27.8° to 53° C. in 3J^ minutes was fed to a 

 guinea pig and resulted in a mild infection. Meat heated from 27.8° to 

 52° in 3 minutes and from 20° to 49.2° in 6 minutes when fed to guinea 

 pigs produced h£avy infections. 



Experiment 14 (April 3 and 4, 1913). — A small piece of meat from a 

 trichinous rat was heated in a beaker of water which was constantly 

 stirred. The temperature rose from 17° to 53° C. in 13 minutes and 

 remained between 53° and 53.6° for 2 minutes. One larv^a afterwards 

 isolated by dissection was inactive except at the anterior end which 

 moved slightly; another was active, though the appearance of its proto- 

 plasm was somewhat altered. 



Another piece of meat was similarly heated from about 20° to 54° C. in 

 about 10 minutes. Larx^ae isolated by dissection were alive and active. 

 Another piece was similarly heated from 28° to 53° in 11 minutes and 

 remained in the water another minute, during which time the tempera- 

 ture rose to a maximum of 53.8°. Larv^as isolated by dissection v^'ere 

 alive and active. Two pieces were heated from 28° to 55° in 13 minutes. 

 One piece was held at a temperature of 55° for i minute, the other 

 piece at the same temperature for 2 minutes. Trichinae isolated by dis- 

 section from these pieces were inactive. Another piece of meat from the 

 same rat was heated from 30° to 54° in 5 minutes and held at a tem- 

 perature of 54° to 54.8° for I minute. Larv^ae isolated by dissection were 

 found to be inactive. 



Experiment 15 (April 9, 191 3). — Small pieces of meat from two 

 trichinous rats were tied in a cloth around the bulb of a thermometer, 

 which was immersed in a beaker of water and heated. The temperature 

 was held at 54.6° to 54.8° C. for five minutes. Ten larvae were after- 

 wards isolated by dissection. All were inactive except one, which showed 

 a very slight movement of its anterior end. 



Experiment 16 (May 16 and 19, 1914). — Portions of the diaphragm 

 of a trichinous rat were heated in a beaker of water stirred constantly 

 over a water bath. Trichinae were dissected out cf the meat after heating 

 and examined under the microscope at room temperature. A portion was 

 heated from 24° to 54° C. in four minutes. Four larv'se examined; i inac- 

 tive; 3 active, sluggish. Another portion was heated from 24° to 53° in 

 6 minutes. Ten lar\'£e examined; all active. Another portion was 

 heated from 23° to 54° in 5 minutes. Twelve larvae examined ; 3 inactive ; 

 9 active but very sluggish; appearance of protoplasm abnormal. 



