A master may be liable for injuries sustained by his servant in consequence of apparent defects in a machine which the latter is using, if on account of his inexperience he does not know the peculiar dangers incident to its use, and if the master cannot reasonably assume that he has such knowledge. An incompetent and prejudicial suggestion of counsel, contained in a question addressed to a witness without any purpose to render the trial unfair, may not result in a mis-trial, when the fact is found that the verdict was not affected thereby.