> 1. 



SECTIOX V 



DISEASES OF THE DIGESTIVE TRACT 



Birds are not subject to the manifold ills of the digestive 

 system that prevail in higher animals and man. at least the 

 list of digestive ailments which we recognize in birds are 

 not so numerous as they are in higher animals. Beginning 

 with the anterior portion of the digestive canal, the mouth, 

 we find its part in digestion relatively unimportant compared 

 to that of the same organ in mammals, and its ailments cor- 

 respondingly fewer and less important. 



The food is not masticated in the mouth as in higher ani- 

 mals, but is swallowed whole, passing into the crop, where 

 it is softened bv the action of the fluids secreted bv that 

 organ and perhaps also by the action of bacteria swallow^ed 

 with it. After maceration in the crop is accomplished, the 

 food passes into the proventriculus (stomach), wiiere the proc- 

 esses of digestion are carried still futher by the secretions 

 (juices) of that organ. The thoroughly soaked and softened 

 food is next received into the gizzard and ground (Avith the 

 pebbles — grit — always present in that organ) to a paste by 

 the action of its strong muscular walls. 



From the gizzard the food passes into the small intestine, 

 where digestion is carried on much as it is in other domestic 

 animals, by the action of the secretions of the intestine, liver 

 and pancreas. 



Domestication has affected the feeding habits of birds much 

 as it has the feeding habits of horses. In the wild state birds, 

 like horses, eat most of the time, but they secure their proven- 

 der more slowly. Under domestication they are fed nutritious, 

 highly concentrated food in a readily accessible form, two or 

 three times daily, and are required to exercise but slightly to 

 get it. Frequent disturbances of digestion, largely due in one 

 way or another to engorgement, is the result. 



OBSTRUCTION OF THE BEAK 



This condition is very rare. Cases have been noted in which 

 an object, such as a sunflower-seed, has become wedged be- 

 tween the rami (branches) of the inferior maxilla (lower por- 

 tion of the beak), and serious trouble has resulted from this 

 pressure; for example, paralysis of the tongue, inability to 

 eat, starvation and death. 



