DETERMINING THE STATUS PRAESENS. 29 



of the hammer. It is usually better, however, to employ ham- 

 mer-to-finger or finger-to-finger percussion. 



The thickness of the over-lying fat or muscular layers 

 does not seriously interfere in this form of percussion. 

 Through practice we learn to select the factors of importance 

 to form an opinion. Deep-lying diseased conditions do not 

 present through tactile percussion specific symptoms, but we 

 may thus obtain valuable information in regard to the boun- 

 daries and consistency of otherwise unavailable organs or 

 parts. Tactile percussion simply supplements and completes 

 palpation and ordinary percussion. 



Determining the Boundaries of an Organ from the 

 Percussion-Sound. 



The boundary of an organ can be determined bv percus- 

 sion only when the organ lies superficially and emits a percus- 

 sion-sound which differs from that of its neighborhood. For 

 this reason the boundary of the heart against the lung or the 

 lung against the bowels may be defined by percussion. 



4. Auscultation. 



By auscultation, applying the ear to a part, we seek to 

 obtain information, through the sense of hearing, as to the 

 physical state or condition of deep-lying organs. For this 

 reason auscultation is practiced upon the heart, lungs and 

 gastro-intestinal tract. 



In human medicine auscultation is usually practiced with 

 the help of instruments {mediate auscultation), the so called 

 stethoscope, etc., being employed. [In veterinary medicine, 

 however, the use of such instruments is very limited, the 

 heavy hair coat materially interfering with and so modifying 

 the sounds that false conclusions may be drawn. To a limited 

 extent the phonendoscope is useful in auscultating heart 

 sounds, but the hairs over the cardiac region should first be 

 thoroughly moistened or oiled]. 



By simply applying the ear firmly to the part, better re- 



