INTERNAL ANATOMY OF BIRDS. 



373 



is retained prior to the gastric digestion. The ossophagus is 

 followed by the provenfriculu-% which is the true stomach in 

 which gastric digestion takes place. This first stomach cor- 

 responds with the cardiac end of the mammal's stomach. The 

 pyloric end is represented by the "gizzard" (G), a large ex- 

 tremely muscular cavity situated 

 below the liver. There are two 

 distinct types of this grinding 

 stomach ; in raptorial birds it 

 consists of a simple membran- 

 ous sac, but in graminivorous 

 birds, which eat hard and not 

 easily digested food, the gizzard 

 consists of a thick muscular 

 cavity which is lined by a hard 

 epithelium. By the muscular 

 action of the walls of the gizzard 

 the food is ground up against 

 the horny walls. In all birds 

 we find in this second stomach 

 small stones, cinders, and grit. 

 These aid in the trituration of 

 the food. They are essential to 

 the health of the bird, hence 

 poultry are given " grit " to eat. 

 This grit should be natural, not 

 sharp needle-like pieces of flint, 

 such as some poultry merchants 

 advertise, which only damage 

 the walls of the gizzard and do 

 not grind the food. Many inflammatory diseases of the gizzard 

 I have traced to this reprehensible practice. The intestine con- 

 sists of two parts, the small and large intestine, and ends in the 

 cavity called the cloaca (GL). The large intestine commences 

 where the two long blind tubes originate, the " csecal tubes " 



Fig. 213.— Alimentart Canal of 

 Fowl. 



Oe, CEsuphagus ; C, crop; S, proveii- 

 triculus ; G, gizzard ; D, duodenum ; Si, 

 small intestine ; Cae, caeca ; /, .lunction 

 of cseca ; R, rectum ; CL, cloaca ; A , 

 anu.s ; L, liver ; Gb, gall bladder ; 0, 

 right lobe of liver ; P, pancreas. 



