Sometimes, especially in individuals who show this tendency during narcosis, a marked obstruction in breathing is met with, attended by increasing cyanosis, a condition due to dropping back or recession of the base of the tongue into the laryngo-pharyngeal space. Changing the position of the head does not improve the breathing, the jaw cannot be pushed forward because the masseter is rigidly contracted and the teeth are clenched tightly. To draw forward the tongue would require a rough procedure, with wedge, gag, and forceps. If a soft rubber catheter or the breathing tube be passed through the nostril into the pharynx the respiratory air streams freely through the tube.