EMPHYSEMA OF THE LUNG. 



moved from the chest, that the lungs maintain their normal contour, in 

 contrast to the variety of vicarious emphysema last described. The 

 same conditions obtain, both with regard to the extent of the malady 

 and to the maintenance of the natural shape of the lungs, in that form 

 of emphysema which arises without mechanical origin, and also in the 

 variety whose source lies in a primary ectasis of the thorax. 



If the entire lungs or their upper portions be the seat of emphysema 

 of much intensity, the anterior pulmonary walls are pushed far down- 

 ward. The left lung often covers the pericardium completely; the 

 right reaches down to the seventh rib ; the heart, usually much enlarged, 

 lies upon the diaphragm in a more horizontal direction. In previous 

 editions of this work there are many erroneous statements with regard 

 to the position of the heart in emphysema. 



An emphysematous lung feels remarkably soft to the touch, like a 

 pillow filled with down. Upon cutting it, a dull, creaking sound is barely 

 perceptible. The inflated tissues of acute emphysema are of a strikingly 

 bright-red and pale hue ; in chronic cases, as a rule, they are exceedingly 

 dark, with here and there irregularly-formed black spots, the produce 

 of conversion into melanin of hematine contained in the former capil- 

 laries. 



Even to a superficial glance, the vesicles are seen to be greatly en- 

 larged, sometimes to the size of a pea or bean, and are of irregular 

 shape. Upon closer examination (of a dried specimen especially) in 

 acute cases, we find, traversing most of the large cysts, a few delicate 

 bands, as vestiges of the lacerated interalveolar septa. In mild de- 

 grees of chronic emphysema, we find perforations of the septa, varying 

 in size and number; in severer cases, the walls are reduced to the con- 

 dition of solitary ridges. At first, the atrophy is limited to the septa 

 between the vesicles of one infundibulum ; but afterward the vesicles 

 of one infundibulum blend with those of its neighbors, by wasting of 

 the intervening walls ; until at last, in the worst stages of the disease, a 

 large part of the pulmonary tissue is converted into a coarse network. 

 As many of the capillaries perish with the septa, the emphysematous 

 tissue is remarkably bloodless and dry. 



Interlobular emphysema forms small cysts, full of air, beneath the 

 pleura, which causes the latter to seem as if lifted by froth. These air- 

 bubbles may be displaced by pressure, thus furnishing an easy means 

 of distinction between vesicular and interlobular emphysema. This dis- 

 placement, however, cannot be produced uniformly in all directions, but 

 only in lines which mark the boundaries of the lobuli. Single lobules 

 are often enclosed, like islands, by a narrow border of minute vesicles. 

 This fact alone suffices to refute the assertion of certain French authors, 

 that, in vesicular emphysema, the air is not enclosed in the air-cell?, but 



