SECTION 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 nnmerons 

 as they are in higher animals. Beginning with the 

 anterior portion of the digestive canal, the month, 

 we find its part in digestion relatively unimpor- 

 tant compared to that of the same organ in mam- 

 mals, and its ailments correspondingly fewer and 

 less important. 



The food is not masticated in the month as in 

 higher animals, but is swallowed whole, passing 

 into the crop, where it is softened by the action 

 of the fluids secreted by that organ and perhaps 

 also by the action of bacteria swallowed with it. 

 After maceration in the crop is accomplished, the 

 food passes into the proventriculus (stomach), 

 where the processes of digestion are carried still 

 further by the secretions (juices) of that organ. 

 The thoroughly soaked and softened food is next 

 received into the gizzard and ground (with 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 



73 



