Guinan v. Famous Players-Lasky Corp. 267 Mass. 501, 521-522. Jordan v. Velozo, 269 Mass. 347, 351. Commonwealth v. Chin Kee, supra.
The permission to perform or make experiments or illustrations in the presence of the jury rested in the sound judicial discretion of the trial judge. Commonwealth v. Snyder, 282 Mass. 401. Jordan v. Velozo, 269 Mass. 347, 351. Posell v. Herscovitz, 237 Mass. 513, 517.