1941. This is also clear from everything in the human body. When anything harmful touches the tiny fibers, either the sensitive parts in the organs or the insensitive parts in the internal organs, the tissues at once contract, putting on such a shape and character that they cannot be harmed, even if this may cause a painful, offensive or unpleasant sensation. The same principle applies to the attempts of evil spirits when they are trying to harm the good.
1941. This may be illustrated by things pertaining to the human body; when, for instance, any offending substance touches the fibrils, or the sensitive parts in the organs, or the insensible in the viscera, the fibers instantly constringe, and put on such a form and quality that they cannot be injured, although assailed by that which is painful, foul, and disagreeable. The effect is similar in the case of evil spirits attempting to injure the good.
1941. Hoc quoque constare potest ab iis quae sunt in corpore humano, illico dum aliquid laedens tangit fibrillas, sive sensiles in organis, sive insensiles in visceribus, fibrae se illico comprimunt, et formam ac qualitatem induunt, ut non laedi queant, tametsi dolorificum, tetrum, inamaenum inde, similiter se habet cum conatibus spirituum malorum, dum laedere volunt bonos.