AS TO SOUNDNESS. 153 
Active. . . Broncheoles. 
ete { Residual air in air cells. 
Elastic walls of air cells. 
Diaphragm. 
Intercostal muscles. 
Nostrils.—These should have a wide enough opening, 
and the muscles ought to be in good tone, otherwise a 
flapping noise like a sheet in a wind takes place. When 
they are rigidly open they are somewhat cone-shaped— 
the base of the cone being the opening and the apex of 
‘the cone being at the part where the fleshy structure gives 
place to the bony canal. When this cone is too small 
‘and the nostrils consequently thrown into rigid contrac- 
tion, a loud blowing noise results, and the horse is then 
known as a “high blower.” 
‘ Lurbinated bones.—These and others form a rigid 
channel through which all the air must pass, and their 
lining is so frequently involved in inflammation during 
catarrh and other diseases, when inflammatory thicken- 
Ing results. This gives rise to a whistling noise during 
inspiration and expiration, and the horse is said to 
be a “whistler.” If the membrane (schneiderian) is 
active at the time and the parts well lined with thick 
mucous, it gives rise to a moist rattling whistle. Should 
there be ulceration and loss of the turbinated bones, 
and the channel by this means widened, a loud snoring 
results, which can be heard when the horse is standing 
quietly in his stall. Nasal polypi are sometimes present 
in this neighbourhood, which discover their presence by 
Active. { 
