EN
The acethylcholine level was determined by pharmacologic method in properly selected experimental and control groups of mice. Selection was made as to the strain, age, body weight and time that elapsed since the induction of experimental infection. After isolation of the diaphragm, inactivation of choline esterase by physostigmin, acetylocholine was extracted in a solution at pH of 3. The contraction of the dorsal muscle in leech, due to the effect of extracts from the diaphragm of infected and control muscles were compared with those that occurred under the influence of colutions obtained from cristalline acethylcholine. The experiments were made at 2, 3, 4, 5, 6, and 12 weeks of infection. The acethylcholine level in the diaphragmatic muscle of Trichinella-infected animals was found to be higher than that of normal ones (fig. 1), and to show an increasing tendency up to the 4th week of infection; the subsequent decrease was lower at 12 than at 2 weeks p. i.