TRACHEOTOMY. 



another way, and uncurls and covers the opening when the food is 

 swallowed. 



The arytsenoid cartilages (fig. 6) are small in the ox : the thyroid 

 cartilages (fig. 7) are large. The interior of the larynx of the ox — 

 the organ of voice — is more simple than in any other domesticated 

 animal. There is neither membrane across the opening, nor are there 

 any duplicatures of membrane resembling sacs within the larynx ; in 

 fact, his voice is the least capable of modulation of any of our quad- 

 ruped servants. 



THE WINDPIPE. 



The trachea, or windpipe, of cattle is small, because much air is 

 not wanted. The ox is not a beast of speed, and he rarely goes 

 beyond the walk or trot. The cartilagino^.s rings are narrow (fig. 9, 

 cut, p. 196), and thick. The interposed ligamentous substance is 

 weak (fig, 10, p. 196). A tube of loose construction is suffi- 

 cient for the portion of air which the ox needs in respiration ; an^ 

 gathering usually the whole of his food from the ground, and gather- 

 ing it slowly, and being longer occupied about i* more freedom of 

 motion, and a greater degree of extension, are reqm te. 



In addition to this, there is no careful and intricate overlapping of 

 the cartilages behind ; they are simply brought into approximation 

 with each other ; and their opposing edges project behind so that 

 they are very loosely bound to the cervical vertebrae. There is no 

 transverse muscle, because the cahber of the tube can seldom or 

 never be much varied, but, by way of compensation, the lining mem- 

 brane of the trachea is dense, extensible, and elastic, and capable of 

 discharging, although imperfectly, a function similar to that of the 

 transverse muscle. At the lower part of the windpipe, the triangular 

 prolongation of cartilage for the defence of the tube in the immediate 

 neighborhood of the lungs is small. The rings of the windpipe of 

 the ox are about 60. 



TRACHEOluMY. 



Although there are few diseases of cattle in which the animal is 

 threatened with suffocation, yet occasionally in blain, in inflammation 

 of the parotid gland, and in those varieties of fever which in the ox 

 are so much characterized by the formation of tumors, there will be 

 pressure on the windpipe, much contracting its caliber, and rendering 

 the act of respiration laborious, and almost impracticable. In inflam- 

 mation of the larynx, to which cattle are much exposed, the distress- 

 ing labor of breathing is scarcely credible. 



Tracheotomy, or the formation of an artificial opening into the 

 windpipe, is an operation very easily and safely performed. The 



