THE LARYNX. 257 



We would, then, say to every horseman and practitioner, study the 

 chai-acter of that portion of the membrane which covers the lower part 

 of the membrane of the nose — that which you can most readily bring into 

 view. Day after day, and under all the varying cu'cumstances of health 

 and disease, study it until you arc enabled to recognise, and you soon Avill, 

 and that with a degree of exactitude you would have scai'cely thought 

 possible, the pale pink hue when the horse is in health — the increasing- 

 blush of red, and the general and uniform painting of the membrane, 

 betokening some excitement of the system — the streaked appearance when 

 inflammation is threatening or commencing — the intensely florid red of 

 inflammation becoiuing acute — the starting of the vessels from their 

 gossamer coat, and their seeming to run bare over the membrane, Avhen 

 the inflammation is at the highest — the pale ground with patches of vivid 

 red, showing the half-subdued but still existing fever — the uniform colour, 

 but somewhat redder than natural, indicating a return to a healthy state of 

 the circulation — the paleness approaching to white, accompanying a state 

 of debihty, and yet some radiations of ci'imson, showing that there is still 

 considerable irritability, and that mischief may be in the wind — the pale 

 livid colour, warning you that the disease is assuming a typhoid character 

 — the darker livid, announcing that the typhus is established, and that 

 the vital current is stagnating — and the browner, dirty painting, inter- 

 raingflinsr with and subduino; the Kvidness, and indicatino' that the e'ame 



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is up. These appearances will be guides to our opinion and treatment, 

 which we can never too highly appreciate. 



THE LARYNX 



Is placed on the top of the windpipe, immediately below and in contact 

 with the pharynx, and is the inner guard of the lungs if any injurious 

 substance should penetrate so far : it is the main protection against the 

 passage of food into the respiratory tubes, and it is at the same time the 

 instrument of voice. In this last character it loses much of its importance 

 in the quadruped, but still in the dumb animal it is a beautiful piece of 

 mechanism. 



The Epiglottis is a heart-shaped cartilage, placed at the superior 

 opening into the larynx, with its back opposed to the phar_)'nx, so that 

 when a pellet of food passes from the pharynx in its way to the oesophagus, 

 it presses down the epiglottis, and by this means, as already described, 

 closes the aperture of the larynx, and prevents any portion of the food 

 from entering it. The food having passed over the epiglottis, it, from its 

 own elasticity, and that of the membrane at its base, and more par- 

 ticularly the power of the hyo-epiglotideus muscle, rises again and resumes 

 its former situation. 



The Thyroid Cartilage occupies almost the whole of the external part 

 of the larynx, both anteriorly and laterally. It envelopes and protects 

 all the rest ; a point of considerable importance, considering the injury 

 to which the larynx is exposed, by our system of curbing and tight-rein- 

 ing. It also forms a point of attachment for the insertion of the greater 

 part of the delicate muscles by which the other cartilages are moved. The 

 other cartilages are the cricoid and two ar^'tenoid. The cricoid, or ring- 

 like cartilage, is placed at the base of the thjToid, connecting it with 

 the trachea or windpipe : the two arytenoid, or ewer-shaped cartilages, 

 form the upper and back part of the larynx, as the thp-oid does the 

 upper fi-ont and lateral portion. It is principally supplied with nerves by 

 the lar_)Tigeal branches of the par vagum and the recurrent nerves ; and 

 there are also frequent anastomoses with the motor nerves of the spinal cord. 



The beautiful mechanism of the larynx is governed or worked by a 



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