Bronchial Vessels 1 99 



end in fine capillaries between the air-cells. Indeed, the capillaries 

 bulge on each side into the cells, being covered only by their thin 

 epithelial pavement. 



The bronchial vessels supply the machinery of the lungs, the 

 pulmonary vessels being occupied with aeration of the blood. The 

 bronchial arteries, two or three to each lung, come from the thoracic 

 aorta or the intercostals; the veins empty into the azygos trunks. The 

 lymphatics end in the bronchial glands, in the root of the lung. 

 These glands are often loaded with particles of carbon which have been 

 brought from the air-cells by the lymphatics. Often they are found 

 calcareous post mortem ; this is when they have been inflamed and 

 enlarged, the salts having remained whilst the softer elements were 

 absorbed. 



The anterior and posterior pulmonary plexus supply pneumogastric 

 and sympathetic filaments. 



EXAMINATION OF THE CHEST 



Percussion is most conveniently carried out by striking the middle 

 finger of the left hand by tips of the partly flexed fingers of the right. 

 The character of the sound thus obtained reveals the comparative 

 density of the tissue beneath. Thus, over healthy lung the note is 

 clear, over cedematous lung it is comparatively dull, and over solid 

 lung, or over liver (with no lung intervening), it is absolutely dull. 

 With a good ear and a clever touch the exact area of heart, of a hepa- 

 tised patch of lung, of an aneurysm or a vomica, can generally be clearly 

 defined. But in the case of serious disease examination should be dis- 

 creetly carried out, lest the patient suffer from exposure, and lest his 

 chest be so shaken as to set up cough or bring on haemoptysis. 



Percussion is resonant in the root of the neck, but the note is not 

 so clear as it is below the clavicles, because the apex of the lung is 

 small. Resonance should be good also along the middle of the cla- 

 vicle. 



On the right side the note begins to get dull from below the fifth 

 rib, because of the decreasing volume of the lung over the liver. Below 

 the liver-dulness the tympanitic resonance of the intestines begins. 



The note is clear over the manubrium, though there is no lung 

 behind that bone (p. 193) ; the resonance being due to vibration in ad- 

 jacent lung-tissue. But it is clearer along the gladiolus, though from 

 the fourth cartilage downwards, and to the left, comes the comparative 

 dulness of the cardiac area (p. 165). The resonance is greater on in- 

 spiration, as the border of the lung glides further over the heart. Below 

 the base of the left lung the tympanitic note of the stomach begins. 



For the sake of comparison, the two sides of the chest must be 

 percussed symmetrically from the supra-clavicular regions downwards, 

 due allowance being made for the area of cardiac dulness. For per- 



