PHYSICAL SIGXS DRAWX FROM AUSCULTATIOX. 439 



tliG sound Avhich on auscultation conveys to the ear the idea 

 of air being drawn tlirougli moderately sized bronchi contain- 

 ing liquid, mucus, blood, or pus, and in its passage producing 

 bubbles of a good size. The sound co-exists with both expi- 

 ration and inspiration. It is the sound present in ordinary 

 bronchitis after the dry stage has been passed and secretion 

 fairly established. It is modified as to its intensity and con- 

 tinuance by the character of the bubbles formed and the force 

 with which the air is sent through the tube. 



This sound may be temporary or permanent, and modified 

 at all times by the quantity of fluid present in the tubes. 



b. Submucous or Sabci^epitant Rclle. — This is to be regarded 

 as a modification of the ' mucous rale.' It is the sound com- 

 parable to the passage of air through the smaller bronchi 

 containing a viscid liquid. When the bubbles produced are of 

 a minute character, it has been likened to the effervescence 

 occurring in liquids containing gas. It may be heard during 

 both the respiratory acts, louder, as a rule, during inspiration. 

 It is indicative of established inflammation, Avith secretion in 

 the smaller tubes, and may be regarded as the intermediate 

 sound found occurring between the ' crepitant ' and ' mucous 

 rale.' 



c. Crepitant Rales. — Of these, several variations are noticed. 

 We, however, only regard — 



(1) The True Crepitant Rale. — To this reference has already 

 been made, and the sound indicated by this term partly 

 described, when spealdng of the changed characters of the 

 pulmonic sounds, under that of ' rough respiration.' 



It consists of a great number of very minute, sharp, crepitant 

 sounds rapidly elicited, and has not inaptly been likened to the 

 sound developed by rubbing a lock of hair between the finger and 

 thumb close to the ear. It is believed to owe its existence to the 

 passage of the air through or to and from the minute bronchi 

 and air-sacs, and by the act of the expansion of these latter. 

 The certainty of this is not beyond a doubt, many viewing this 

 sound as a ' friction ' sound, and of pleuritic origin. It is heard 

 chiefly or only during inspiration. It is the sound which is 

 usually developed in the outset of pneumonia, although often 

 in such cases we find this pure ' crepitant rale ' much modified. 



(2) Modified or Secondary Crepitant Rale. — This is the name 



