101 



formed of cartilage, in order that, by its gradual yielding resist- 

 ance, it may neutralize almost any force that may be applied 

 to it. 



When we open the nostril, we see the membrane lining the 

 whole cavity of the nose, by the color of which, much more than 

 by that of the lining of the eye-lids, we judge of the degree of 

 fever, and particularly of inflammation of the lungs, or of any 

 of the air passages. The cut above shows the ramification of the 

 arterial and venous blood-vessels on this membrane. Certain 

 ulcerations on it also betray the existence of glanders. 



The nasal cavity is, on either side, ocfupied by two bones, 

 which, from their being rolled up somewhat in the form of a 

 turban, are called the turhinated or turban-shajied bones, (s s, 

 Fig. 3.) ; part of the cartilage is cut away in our cut in order 

 to display them. They are as thin as gauze, and perforated, like 

 gauze, with a thousand holes. Between them are left sufficient 

 passages for the air. ^Spread out, they would occupy a consider- 

 able surface. Over them is spread the substance or pulp of" the 

 olfactory nerves, whicli makes them the seat of smell ; and they 

 are thus expanded, because by the sense of smell, the horse must 

 in a great degree "supply the want of that of touch. They also 

 enable him to distinguish his proper herbage, detect distant dan- 

 ger ; and they, like the windings of a horn, give loudness to his 

 voice. 



The extension of the nostril at the lower part of these cavi- 

 ties is an important part of the face, and intimately connected 

 with breeding, courage, and speed. The horse can breathe only 

 through the nose. All the air which goes to and returns from 

 the lungs, must pass through the nostrils. In the common act 

 of breathing, these are sufficiently large ; but when the animal 

 is put on his speed, and the respiration is quickened, these pas- 



