In cases where a violent effort has preceded death, violet-coloured spots containing venous blood may be perceived on the surface of the lungs, and which are true ecchymoses, occasioned by the rupture of some small vessels. Such phenomena must be carefully distinguished from the livid, black spots, which have been observed in cases of narcotic poisoning, and which are characterised by a more dense, and less crepitating texture. In this stage of the dissection, we may conveniently extend our examination into the trachea, and bronchiæ, and observe whether these tubes contain frothy mucus as in drowning; coagulated blood, as in pulmonary hemorrhage; pus, as in the event of the rupture of a vomica or impostume; or ropy and tenacious mucus or lymph, as in croup, tracheal inflammation, and bronchitis; or chyme, as may occur in cases of intoxication, and diseases of the brain, where vomiting has taken place during a state of insensibility.[31] We shall at the same time be enabled to ascertain whether any mechanical obstruction, from the presence of foreign bodies, exists in the pulmonary passages, and which might have occasioned death to the patient, as related under our history of suffocation, vol. ii, p. 57.