536. _The purity of the blood is influenced by the condition of the lungs._ When the bronchial tubes and air-cells have become partially impervious to air, from pressure upon the lungs, from fluids in the chest, from tumors, or from the consolidation of the cells and tubes from disease,--as inflammation, or the deposition of yellow, cheesy matter, called tubercles,--the blood will not be purified, even if the air is pure, the lungs voluminous, and the respiratory movements unrestricted, as the air cannot permeate the air-cells. _Observations._ 1st. The twenty-three who escaped immediate death in the Black Hole of Calcutta were soon attacked with inflammation of the lungs, by which these organs were consolidated, and thus prevented the permeation of air into their cells. This disease of the lungs was caused by breathing vitiated air. -=-=-=-=-=-=-=-=-=-=-=-= 535. Mention some of the effects of mental depression upon the body. What is related by Lænnec? 536. Does the condition of the lungs influence the purity of the blood? Mention some of the conditions that will impede the oxydation of blood in the lungs. What occurred to those persons who escaped death in the Black Hole of Calcutta? -=-=-=-=-=-=-=-=-=-=-=-= 2d. One of the precursory symptoms of consumption is the feeble murmur of respiration in the upper part of the lungs. This condition of these organs is produced by, or frequently follows, mental depression, the breathing of impure air, the stooping position in standing or sitting, and the restriction of the movements of the ribs and diaphragm. 3d. Persons asphyxiated by carbonic acid, water, strangling, or any noxious air, after resuscitation, are usually affected with coughs and other diseases of the lungs. 537. COLDS and COUGHS are generally induced by a chill, that produces a contraction of the blood-vessels of the skin; and the waste material, which should be carried from the body by the agency of the vessels of this membrane, is retained in the system, and a great portion of it is returned to the mucous membrane of the lungs. For such is the harmony established by the Creator, that if the function of any portion of the body is deranged, those organs whose offices are similar take on an increased action.