2o6 Journal of Agricultural Research voi. xvii, No. s 



from their normal environment, and it is possible also that they may be 

 able to replace waste through the absorption of nutritive materials from 

 their host. 



A natural corollary to experiments on the effects of hypotonic solutions 

 are experiments on the effects of hypertonic solutions. A typical 

 example of such an experiment is one in which decapsuled larvae were 

 kept for 22 hours in a molar solution of dextrose. At the end of this 

 time they were found to be partially uncoiled; their protoplasm was dull 

 in appearance; the cuticle was wrinkled, particularly in the posterior 

 portion of the body; the body wall was wrinkled; and the cells of the 

 esophagus were indistinct. After having been transferred to and kept 

 in 0.7 per cent salt solution overnight, they were found to be tightly coiled 

 and normal in appearance. Similar results were obtained in a repetition 

 of this experiment. 



So far as concerns the purposes of the present paper, the foregoing 

 observations are of interest because they show that trichinae freed from 

 their cysts by artificial digestion may be kept alive for a long time in 

 physiological salt solutions, in water, and in certain hypertonic solutions, 

 and that, although within a temperature range the upper limit of which 

 does not exceed 40° C. their longevity decreases as the temperature at 

 which they are kept is raised, they do not in any case die quickly. 



EXPERIMENTS WITH DECAPSULED LARVAE 



Inasmuch as trichina larvae that have been freed from their cysts by 

 digestion of finely chopped trichinous meat in artificial gastric juice ^ at 

 a temperature of 38° to 40° C. for a period of about 20 hours can be kept 

 alive for long periods of time, they can be conveniently used in experi- 

 ments on the effects of heat. In a medium such as a 0.6 per cent or 0.7 

 per cent solution of sodium chlorid, but also in plain water if not kept 

 too long, they display more or less activity even at ordinary room tem- 

 peratures but commonly assume a posture in which they are tightly 

 coiled spirally; and their movements are often limited to a tightening or 

 loosening of the coil. Their protoplasm, when unaffected by heat or 

 other injurious agents, exhibits a certain brilliancy in appearance; and 

 pigment in the cells of the alimentary tract, especially of the esophagus, 

 gives them a distinct brownish color. After a little experience, depar- 

 tures from the normal both as to their behavior and appearance of their 

 protoplasm can easily be detected by microscopic examination. As a 

 rule, in experiments in heating decapsuled larvae, the larvae were placed 

 in a beaker or test tube containing sometimes water but usually a phys- 



' The following fluid has yielded satisfactory results: 



Scale pepsin (U. S. P.) 2. s gm. 



Sodium chlorid 2 gm. 



Hydrochloric acid (sp. g. 1.19) 10 cc. 



Water. 1,000 cc. 



