AUSCULTATION. oo 



ordinarily the case if the effusion be recent or inconsiderable — to the 

 inferior part. It will increase or diminish according to the progress or 

 diminution of the effusion. There is no measuring the effusion by sound ; 

 but we may throw it by the position of the animal into a place where 

 percussion can easily detect it. M. Leblanc observes that, taking absence 

 or deadness of sound to indicate the presence of water, the lungs are 

 supposed to be permeable; otherwise, the deadness might as much 

 depend upon density of the pulmonary tissue as upon the presence of 

 water; still, there is a method of ascertaining from which it proceeds, 

 viz. by placing the horse in that position in which the fluid will accu- 

 mulate in the fore part of the chest, and then, should the posterior part 

 still utter a dull sound, we may conclude that the lungs are hepatized. 

 Furthermore, the dead sound may be partial, owing to local pulmonary 

 condensation, circumscribed indurations, &c. &c. 



AUSCULTATION. 



Auscultation — from aiiscultare, to listen — consists in the perception, by 

 the mediate or immediate application of the ear, of the different sounds 

 generated in the lungs, with a view of determining the normal or anormal 

 condition of those organs, and, in the latter case, of aiding our opinion on 

 their diseases. 



Mediate auscultation is effected through the intervention of the 

 stethoscope ; immediate, through the direct application of the ear to the air- 

 tube, or to the walls of the cavity of the chest. We prefer immediate to 

 mediate auscultation for the following reasons : — 1st, the stethoscope is 

 extremely inconvenient to apply; 2dly, supposing, however, this were 

 not the case, the stethoscope possessing no power of augmenting the 

 sound, but only being the means of conveying it more directly to the ear, 

 no advantage attends the use of such an instrument; 3dly, in human 

 medicine, the application of the ear would prove objectionable both to 

 surgeon and patient, hence by the surgeon the adoption of the stethoscope: 

 this is not our case. 



Immediate auscultation. — During examination the animal should 

 be kept quiet : his attention being engaged by a little hay or corn. 

 During the silence of the night is the auscultator's best time. The ear 

 should be lightly and accurately applied. After all, should the sound 

 remain indistinct, the respiration may be increased by exercise. The 

 nasal cavities, the larynx, the trachea, and the lungs, are the parts to be 

 auscultated ; and the modifications of the healthy sounds must be well 

 studied in order not to confound them with such as arise under disease. 



The respiratory murmur is the normal sound heard within the 

 parenchyma of the lungs during the entry and exit of the air, or rather 

 at the time of their healthy dilatation and contraction. This sound is 

 difficult to describe : once heard, however, in a young well-bred lean 



