214 Journal of Agricultural Research voi. xvii, no. ? 



In the following tests portions of the diaphragm of another rat were 

 heated. A portion was heated from 24° to 54° C. in 5/^ minutes. Ten 

 larvae examined; 9 inactive; i active, very sluggish. A portion was 

 heated from 24° to 52° in ^}4 minutes. Ten larvae examined; all active, 

 lively. A portion was heated from 24° to 58° in 3X minutes. Ten 

 larvae examined; all inactive. A portion was heated from 26° to 53° 

 in 3>2 minutes. Five larvae examined; all active but not very lively. 

 A portion was heated from 26° to 55° in 4 minutes. Twenty-three 

 larv^ae examined; 21 inactive; 2 active, very sluggish. A portion was 

 heated from 24° to 52.6° in 9 minutes. Twelve larvae examined; 2 in- 

 active; 10 active, but very sluggish ; appearance of protoplasm abnormal. 

 A portion was heated from 23° to 52.9° in 2% minutes. Eight larvae 

 examined; all lively. A portion was heated from 22° to 52° in 3^4 min- 

 utes. Twenty-four larv^ae examined; all lively. 



Experiment 17 (May 20, 191 4). — Portions of the diaphragm of a third 

 rat were heated as in Experiment 16, but more gradually. Examination 

 was made as in Experiment 16. A portion was heated from 26° to 53° C. 

 in 12K minutes and cooled to 48.8° in 5 minutes. Sixteen larv^ae exam- 

 ined; all active, but sluggish; appearance of protoplasm duller than nor- 

 mal. A portion was heated from 23.2° to 52° in 14 minutes and cooled 

 to 46° in 7 minutes. Thirteen larvae examined; all active, fairly lively 

 but not as vigorous as unheated larvae ; no conspicuous change in appear- 

 ance of protoplasm ; larvae not coiled as tightly as normal larvae. A por- 

 tion was heated from 23° to 55° in 16 minutes and cooled to 50° in 5 

 minutes. Fifteen larvae examined; all inactive; protoplasm dull and 

 dead in appearance. A portion was heated from 37° to 54° in 9 minutes 

 and cooled to 49.4° in 6 minutes. Twenty-three larvae examined; all 

 active but very sluggish; protoplasm dull and dead in appearance. A 

 portion was heated from 27° to 54° in ii^ minutes and cooled to 49° 

 in 5 minutes. Twenty-four larvae examined; 16 inactive; 8 active but 

 very sluggish; protoplasm dull and dead in appearance. 



Experiments on encysted trichinae were made by the junior writer as 

 follows : 



Experiment 18. — Small pieces of meat from a rat killed one month 

 after infection with trichinae were heated in a physiological salt solution to 

 52°, 53°, 54°, and 55° C, respectively, and then allowed to stand in a 

 refrigerator for two days. The larvae were then freed from their capsules 

 by teasing out the meat, and examined directly. Those heated to 52° 

 were still tightly coiled, although a number of loosely coiled larvae were 

 also seen. Most of the larvae heated to 53° were uncoiled, but a few 

 were coiled normally. Those heated to 54° and 55° were entirely 

 uncoiled, dull in appearance, and failed to become active when warmed. 

 Experiment 19. — Larger pieces of meat from a trichinous hog were 

 heated as in the experiment just described, kept in a refrigerator for 

 two days, and then fed to mice. The post-mortem examinations yielded 

 nesrative results in all cases. 



