AUSCULTATION. 87 



resembles the sound of frothing of beer in a large glass. Leblanc has 

 given it the name of the spumous rale. 



The DRY RALE is a sound extremely variable in its nature, being at 

 one time engendered within the bronchi, at another, but the rever- 

 beration of a sound originating within the pulmonary tissue. It is 

 comparable to a growling bass tone, mingled with deep supplementary 

 respiration. This rale, always denotive of dryness of the bronchi, is 

 especially manifested at the commencement of acute bronchitis : its 

 duration is always very short. By some the sihilous rale is classed among 

 bronchial sounds : in our opinion it more properly belongs to the pul- 

 monary sounds. 



Bronchial respiration is the loud dry sound emitted by the air 

 within the bronchial tubes at such times as some obstacle prevents its 

 free passage into the air-cells. The sound resembles that produced by a 

 rush of air through a tube of tolerable dimension, or the noise of sawing, 

 or such as is occasioned by the rubbing of two planks of wood one 

 against the other. The detection of this sound is easy, and at the same 

 time of importance, from its being indicative of alterations, either in the 

 lungs or pleura, tending to create obstruction in the vesicular tissue : 

 there can be no doubt of its being occasioned by the rushing of the air 

 in and out of the large bronchial tubes. It is less audible in expiration 

 than in inspiration. In hepatisation of the pulmonary tissue the bron- 

 chial sound is heard along the line of demarcation between the hepatised 

 part and that which is only yet infiltrated. It becomes augmented as 

 hepatisation proceeds ; diminished, with its absorption. 



In effusion into the chest., it is as soon as the fluid has reached the 

 height of the lower third of the cavity, and, consequently, as soon as the 

 inferior border of the lung, from being inundated, becomes impervious 

 to air, that bronchial respiration is discovered ; and especially in pleuro- 

 pneumonia, when the lung is hepatized and maintained in the fluid by 

 false membranes, is the sound distinct. In the horse, both in recent and 

 chronic efiusions, the sound is ordinarily heard upon the same level at 

 both sides ; but in dogs and ruminants it is audible but on one side. 



Acute pleurisy^ at its commencement, is likewise characterised by 

 bronchial respiration. In this case, it is synchronous with the small and 

 short inspiration, and catching of the breath, owing to the sharp twitching 

 pains the animal feels every time he dilates his chest ; and it is accom- 

 panied with a general confused sort of noise which renders its detection 

 extremely difiicult. 



Pulmonary emphysema, in the latter stages, is also denoted by 

 bronchial respiration, the murmur being hardly or not at all perceptible. 

 Audible in inspiration, but more so in expiration, it has been divided 

 into ascending and descending sounds. Almost always it is accompanied 

 by both crepitous and sibilous rale. 



