ON EMPHYSEMA OF THE LUNGS. 633 
respiratory murmur is extremely indistinct, or even completely 
extinct, and in its place a slight sibilous rale only is heard, even 
during’ the forced inspirations that precede the act of coughing. 
These indications will be confirmed by the long continuance of 
the disorder, and the existence of an habitual dyspnoea, occa¬ 
sionally aggravated by asthmatic paroxysms. 
When the disease is so far advanced as to form large vesicular 
cavities under the pleura, its presence may be recognised by a 
sound heard during inspiration or coughing, which is quite pa¬ 
thognomonic, and described by Laennec under the appropriate 
name of the crepitous rale with large hubbies. The sound of 
this rale he compares to that which would be produced by blow¬ 
ing into half-dried cellular membrane. We have repeatedly 
verified the accuracy of this comparison, and have uniformly 
found on dissection that the sound in question was produced 
either by an extreme state of vesicular emphysema, or by the 
interlobular form of the disease : we have often found these 
alterations on dissection in cases where this premonitory sound 
was never discovered. 
There is another stethoscopic sound which Laennec describes 
as belonging exclusively to interlobular emphysema, but which 
we have heard on more than one occasion, in cases of vesicular 
emphysema where the ruptured air-cells projected above the 
surface of the lung. We allude to the “friction of ascent and 
descent ,” as Laennec terms it, which is a sensation or sound of 
one or more bodies rubbing against the ribs, and rising and 
falling during the alternate movements of inspiration and ex¬ 
piration. The friction of ascent takes place during inspiration, 
the friction of descent accompanies expiration, and is much 
more constantly audible than the other sound. Most commonly 
the friction seems to take place against the costal pleura; at 
other times it seems to have its site against the diaphragm or 
mediastinum, or between the lobes of the lungs. These sounds 
are sometimes accompanied by a crepitation perceptible to the 
hand. 
Treatment. —As pulmonary emphysema must, in almost every 
instance, be regarded as an accident , caused by some prior dis¬ 
ease of the lung, the first indication should obviously be to 
remove the original disease, as the most effectual means of 
removing its effect, or, at least, of preventing its farther exten¬ 
sion. This is, perhaps, as much as we can reasonably hope to 
accomplish in this case, as it is difficult to conceive how any 
method of treatment should restore that portion of lung which 
has once become emphysematous to its original healthy con¬ 
dition. M. Laennec, however, is of opinion that this affection 
VOL. V. 4 Q 
