86 DISEASES OF THE LUNGS. 



Rales or rattles is the name given by Laennec to such unnatural 

 sounds as may attend the entry or exit of air through the air-passages. 

 This term, which has been restricted in its signification to the noise heard 

 in the windpipe just before death, must here be considered to apply in a 

 general way to every anormal respiratory sound. In respect to the 

 places whence proceed these pathological pectoral sounds, they have 

 been classed as follows : — 



r Humid or Mucous Rale, 

 Bronchial Sounds ....■< Dry Rale, 



C Bronchial Respiration. 



rCrepitous Rale, humid or dry, 

 Pulmonary Sounds ....-{ Sibilous Rale, 



t_Cavernous R^espiration. 



^, , ^ , C Guggling or gurgling Sound, 



Pleural Sounds ..•••? t> ^ i- r.r o a 



C Rumblmg or grumblmg Sound. 



The MUCOUS rale issues principally from the bronchial tubes. It 

 may be compared in sound to the bursting of bubbles of air occasioned 

 by blowing through a pipe into soapy water. It is caused by the 

 presence of mucus or other fluid. Its existence will be temporary or 

 permanent, according as the mucus or fluid continues or not within the 

 tubes : sometimes it becomes converted into the sibilous rale. Cough 

 excited by compression of the throat, by occasioning the expectoration 

 or displacement of the mucus, sometimes extinguishes these sounds ; at 

 other times it creates them. Frequently an accumulation of mucus 

 within one large or several small divisions of the bronchi will cause 

 suspension of the respiratory murmur in the interior of the lung, leading 

 one to believe the lung is hepatised : one only need trot the horse, 

 however, to dissipate any doubts on this head. According as the air 

 meets with resistance from the density of the secretions will the bubbles 

 thereby created be large or small*. Large bubbles ordinarily occasion a 

 noise like the crackling of a pump-sucker falling after it has been raised. 

 The same sound often accompanies the sibilous rfde. It is observable in 

 catarrhal bronchitis when plastic mucosities abound. This sound is 

 heard most distinctly behind the shoulder, opposite to the large divisions 

 of the bronchi : at times it is audible even at the termination of the 

 windpipe. 



The MUCOUS rale with large bubbles becomes perceptible in simple 

 bronchitis and in the second stage of broncho-pneumonia. It is also 

 created by the effusion of fluid into the bronchi, in consequence of 

 destruction of the cartilaginous rings, either from mortification or the 

 bursting of vomica or abscess into the pipe; in which latter case the rale 

 becomes cavernous. Small hubbies are formed when the fluid possesses 

 but little vicosity, or becomes frothy, as in haemoptysis, and the rale 



