Loomis also recognizes its value, but makes this qualifica-
tion : " Prolonged expiration, if unattended with alterations
of quality, is insignificant ; or, if it is low-pitched, it furnishes
no evidence of tubercle."
Put, while there is general agreement as to the value of the
sign, with certain qualifications, there is diversity of Cheap Ampicillin opinion
as to Ampicillin 500 Mg the immediate physical cause.
The most generally-accepted theory is, that the vesicular
structure of the lung is so substituted by tubercular deposit
that it becomes Buy Ampicillin Online a better conductor of expiratory sounds, which,
in normal states of the vesicular murmur, are soon lost after
the commencement of Buy Ampicillin the expiratory act. The normal vesicu-
lar murmur is simply converted into bronchial respiration,
which is frequently as long or longer than inspiration.
Skoda, however, suggests the theory of " some obstruction
to the egress of the air from the lungs," and he expresses his
PEOLONGED EXPIEATIOTT. 233
belief that " the impediment is, in' most cases, caused by a
swelling of the lining membrane of the bronchial tubes." Ex-
ceptionally, he explains it by what he calls "a law of conso-
nance," and this is manifested only in cases of consolidation
of lung-tissue.
These are, I believe, the general outline views held by aus-
cultators as to the immediate physical cause of prolonged ex-
piration when heard in connection with suspected tubercle.
The normal vesicular expiration, which is low in pitch, and
averaging, according to Fournet, about one-fifth the duration
of inspiration, is, by virtue of consolidated lung-structure, con-
verted into bronchial expiration, which is relatively more pro-
longed, more intense, and of higher pitch, than the vesicular.
According to this generally-received view, prolonged ex-
j)iration is heard only in connection with tubercular deposit ;
and, while the theories of "conduction" and "consonance"
may be rational and philosophical, when such deposit is pres-
ent, they are nevertheless unsatisfactory, as a general state-
ment, from the fact that the abnormal murmur is often pres-
ent when tubercular infiltration is extremely limited ; nay,
more, it is frequently observed when no tubercles can be de-
tected, and when no sibilant or sonorous rales indicate swell-
ing of the bronchial mucous membrane.
In such cases, what is the value of the sign ? and what
does its presence indicate? These questions constitute the
text of my paper, Purchase Ampicillin and to their answer I shall briefly direct at-
tention.
In the first place, I may be permitted to state that I am
quite sure there are two errors copied into the majority of our
text-books on physical diagnosis in reference to prolonged ex-
piratory murmur: the fii^st is in attaching too much value to
it as indicating the actual presence of tubercle ^ the second is
in Ampicillin 500mg ascribing, without exceptional qualification, the immediate
physical cause of the sound to the presence of tubercle.
In rejecting, as a general unqualified statement, both the
" tubercular " and the " bronchial congestion " hypotheses, I
offer, as a substitute, the more rational one, in my judgment,
of the leant of pulmonary elasticity. This is certainly more
in harmony with anatomical facts, with the physiology of the
234 PEOLOKGED EXPIEATION.
respiratory act, and with the clinical history of many cases in
which prolonged expiration is observed.
It will be remembered, in connection with this explanation,
that the substance of the lung is highly elastic ; no other por-
tion of the body is so largely composed of Buy Acillin elastic fibres.
" The sub-serous areolar tissue," says Gray, " contains a
large portion of elastic fibres. . . . Between the vessels and
in the interstices between the lobules, there is a quantity of
j'-ellow elastic tissue, which giv^es firmness and resiliency to the
pulmonary structure,"
The walls of the terminal bronchial tubes, the air-cells,
and the intercellular passages, are formed by a peculiar inter-
lacing of longitudinal elastic bundles with fibrous tissue, with-
in which is ]3laced a continuous series of circular muscular
fibres ; so that the entire parenchyma of the lung may be said
to be a mass of elastic and contractile tissue.
Now, in the condition of normal elasticity of the air-cells
and intercellular passages, inspiration is" relatively longer than
expiration ; for the reason, perhaps, that the air, when it enters
the Order Ampicillin smaller bronchial tubes and air-cells, meets with resistance
from their contractility / whereas, in atonic states of this elas-
tic property, inspiration and expiration become more nearly
alike in duration; in other words, the vesicular approaches
more nearly to the bronchial Ampicillin 500 expiration. And, in proportion
as they become more alike in dm'ation, they are also, of course,
more or less mixed in quality.
In Online Ampicillin accounting, therefore, for the physiological disturbance
between these two acts — the faintly-heard vesicular murmur
gradually approaching the bronchial, and finally becoming
more prolonged than inspiration — we naturally inquire into
the forces and functions of ordinary respiration. What are
these forces ? And how are they disturbed ?
The limit of my paper will only allow me to inquire into
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