632 
ON EMPHYSEMA OF THE LUNGS. 
through whose lungs a large quantity of blood is constantly in 
circulation, the dyspnoea which ensues may be so great as to 
terminate rapidly in asphyxia. But when, as is much more 
frequently the case, the emphysema commences slowly and 
proceeds gradually, the disease is in itself seldom attended with 
any immediate danger, although it renders the organ obnoxious 
to serious or even fatal effects from contingent pulmonary dis¬ 
ease, which in a healthy lung might be borne with comparative 
impunity. 
The difficulty of breathing which accompanies this disease is 
constant, but is aggravated by paroxysms, which are irregular 
both in the period of their return and their duration ; it is like¬ 
wise increased by all causes which usually increase dyspnoea 
from whatever source arising, such as the action of digestion, 
flatulence in the stomach or bowels, anxiety, living in elevated 
situations, strong exercise, running, or ascending a height, and 
above all by the supervention of an acute catarrh, to which, as 
already stated, persons affected with emphysema are peculiarly 
liable. Between the paroxysms there is no fever, and the pulse 
is generally regular. In slight cases the complexion and habit 
of body are little altered; but when the affection is more con¬ 
siderable, the skin usually assumes a dull earthy hue, with a 
slight shade of blue interspersed, and the lips become violet, 
thick, and swollen; there is likewise more or less of cough 
usually present, though it is sometimes so slight as to escape 
the notice of the patient: the expectoration generally consists 
of a greyish viscid mucus. These symptoms may, however, be 
considered as appertaining more properly to the disease of the 
bronchi, with which the emphysema is complicated, than to the 
emphysema itself. 
When the emphysema is confined to one lung, or is much 
greater in one than in the other, the side most affected is per¬ 
ceptibly larger than the other, its intercostal spaces are wider, 
and it yields a clearer sound on percussion. If both sides are 
affected equally, the w r hole chest yields a very distinct sound, 
and, instead of its natural compressed shape, exhibits an almost 
round or globular outline, swelling out both before and behind : 
this conformation of the chest is sometimes so remarkable as to 
render the existence of the disease evident from simple inspec- 
tion # . 
The pathognomonic signs of this disease are furnished by a 
comparison of the indications yielded by percussion and aus¬ 
cultation ; for while the sound elicited by percussing the chest 
over the part affected is perfectly clear, or even tympanitic, the 
* Laenncc , Op. Cit. 
