304 Veterinary Medicine. 



and Roger presents at a glance the relations of these different 

 sounds and their significance. 



Blowing or Hissing Murmurs. 



Blowing murmur 1 ( Narrowing of the auriculo-ventricular 



before the first \ ] orifice. Vegetations or coagula on 



sound. j (. the valves. 



f Strongest toward the base of \ Narrowing of the 

 I the heart. Propagated / aortic opening, 

 along the great arteries. 

 Blowing murmur with "| Narrowing of the 



the first sound. ' Strongest toward the apex of j pulmonary artery 



the heart. Not propaga- \ or insufficiency of 

 ted in the great arteries. | the auriculo-ven- 

 [ J tricular valves. 



„, . ... 1 Double rushing sound heard f Insufficiency of the 



Blowmg murmur with I ^^^^ t^e grelt arteries, at J arterial (semi- 

 the second sound. J each beat of the heart. 1 lunar) valves. 



„, . c^ "(Double rushing sound in 1 Aneurism (dilata- 



Blowmg murmur after I ^ . ^ j^ ^ ^ I j ^ ^^ 



the second sound. | of the heart. j aorta. 



From the table it will be seen that each orifice in the heart maj' 

 become the seat of two perfectly distinct and independent mur- 

 murs ; one due to constriction of the orifice in which case the 

 sound is produced with the onward progress of the blood wave ; 

 and one due to dilatation of the orifice or insufficient closure of it 

 by the valves, when the sound is due to a recoil or regurgitation 

 of the blood. There is a further sound due to mere roughness of 

 the valves in cases of disease when the sound will be with the nor- 

 mal current of blood, though a second or regurgitant hiss is often 

 heard from the valves being at the same time insufficient to close 

 the orifice. Another blowing murmur is usually heard over the 

 heart and coincident with its first .sound in the bloodless state 

 (anaemia) . This is not necessarily connected with any diseased 

 condition of the heart itself. 



The nature of these murmurs differs in special instances. 

 They may resemble the soft whisper of the words who or awe, of 

 the double letter «, or the single letter r, according as they are 

 .soft or hard and purring. 



The pericardial murmur, caused by the rubbing of the dry 

 roughened surface of the serous membrane covering the heart on 

 the correspondingly dry rough surface of the same membrane, re- 



