2IO Journal of Agricultural Research voi. xvii, no. s 



Experiment 7 (December 19, 191 4). — Decapsuled larvae, isolated by 

 artificial digestion from meat of a trichinous hog, were heated in 0.6 per 

 cent salt solution in a corked bottle over a water bath. The temperature, 

 determined by a thermometer inserted through the cork, rose from 24.4° 

 to 56.7° C. in 44 minutes and remained at this maximum for 30 seconds, 

 after which the bottle was allowed to cool, the temperature dropping to 

 34.4° in 38 minutes. Three hundred and sixty-five of the larvse were 

 then examined on a warm stage and all were found to be inactive. As 

 a control on the results of this experiment 22 unheated larvae from the 

 same source were examined on a warm stage; 4 were inactive, 18 active. 



Experiment 8 (April 6, 191 5). — Decapsuled trichinae, isolated by 

 artificial digestion from a mixture of meat from six hogs, were kept 7 

 days in 0.6 per cent salt solution at ordinary room temperature. Some 

 were then heated in a beaker of the salt solution, constantly stirred, over 

 a water bath. The temperature rose from 20° to 54° C. in 7 minutes, and 

 remained at this maximum for 30 seconds, after which the beaker was 

 allowed to cool. Examination of some of the larvae from the beaker 

 showed that most of them were more or less uncoiled, but some were 

 tightly coiled and practically normal in appearance. The beaker was 

 kept until the following day at ordinary room temperature and the con- 

 tents again examined. The great majority of the worms were still alive, 

 but most of them were not tightly coiled. 



Another lot of lar\^ae from the same source was heated in a similar man- 

 ner but more slowly, the temperature rising from 23° to 54.8° C. in 56 

 minutes, remaining at 54.8° for i minute, after which the beaker was 

 allowed to cool. Four hundred and seventy larvae were examined; all 

 were uncoiled, and their protoplasm was rather dull in appearance. The 

 beaker was kept at room temperature until the following day, when 

 examination of 200 larvae showed that all were dead. 



Subsequent experiments on the effects of heat on decapsuled larvae 

 were performed by the junior writer. 



Experiment 9. — Decapsuled trichinae in a physiological salt solution 

 were placed in a test tube and a thermometer immersed in the solution. 

 The test tube was placed in a beaker of water, which was heated rapidly 

 until the thermometer registered 55° C. This temperature was attained 

 in four minutes. The contents of the test tube were immediately trans- 

 ferred to a stender dish and allowed to cool. The larvae were then exam- 

 ined. Nearly all were unaffected. A few days later this experiment 

 was repeated, increasing the time of heating to about eight minutes. 

 Similar results were obtained. 



