158 CHOKING. 



or on the nature of food. The causes included under the 

 first head are, Istly, Any influence which may favour the 

 contraction of the throat or gullet on the object swallowed. 

 This is a cause frequently operating in man, and dependent 

 chiefly on mental operations. Thus what difficulty some 

 persons experience in swallowing a small pill, and when by 

 bread crumbs or water they can feel satisfied the pill has 

 passed on into the stomach, they still experience a choking 

 sensation. It is this choking sensation or irritable condition 

 of the muscular coat which persists after animals have been 

 relieved of an obstruction, and which induces a relapse if 

 they are allowed cut roots. 2ndly, Inflammation or ulcera- 

 tion of the throat and gullet favour choking. The ulceration 

 which follows bad accidents of this description, and which is 

 especially troublesome a week after an animal has been re- 

 lieved, often causes a dangerous accumulation of alimentary 

 matters low down in the oesophagus. Srdly, Organic disease 

 of the oesophagus, especially constrictions such as are observed 

 in crib-biting horses. 4thly, Injuries and diseases of the 

 salivary apparatus or organs of mastication, whereby food is 

 imperfectly chewed and moistened. If the parotid ducts in 

 a horse are both opened, so as to allow of the escape of the 

 secretion, the animal soon suffers from impaction of the gul- 

 let. 5thly, Voracious appetite and rapid deglutition of bulky 

 or dry food. 



The second class of causes may be classified under three 

 heads. The object to be swallowed may be sharp -pointed, 

 too large, or too dry. Amongst the first we include fish 

 bones, which are very troublesome in puppies: large bones 

 which transfix the oesophagus in different parts "f its course 

 in the dog ; and thorns, such as the one represented here (see 

 Fig. 80), and which are occasionally met with in hay. 



The oesophagus is so dilatable that objects are not often 



