Organs of Nutrition 



'35 



portion known as the proventriculus is the smaller, and 

 contains very active digestive glands, sometimes ar- 

 ranged in patches, but more usually forming a band. If 

 the lower part of the oesophagus of an English Sparrow 

 is removed, slit open and washed, these glands can be 

 easily seen, being more of a rose tint than the paler tissue 

 of the portion nearer the mouth. The walls are thicker 

 in this glandular area. This can be seen to better ad- 

 vantage in a young chicken, 

 where the glands take the 

 form of conical protuber- 

 ances which dot the entire 

 surface. Nature has pro- 

 duced curious modifications 

 of this typical fore-stomach, 

 as in snake-birds, whicn have 

 the glands of this portion en- 

 closed in a sac, in shape not 

 unlike a small crop. Here 

 the food is softened and acted 

 FIG. 106. Glands of the stomach of a upon chemically by the secre- 



young chicken. ,. ,, 



tions from the walls. 



The second division of the stomach is the gizzard, 

 an organ made to perform most powerful compressing 

 motions, thus crushing and macerating the food, so that 

 when passed on into the intestine, every particle of nour- 

 ishment may be extracted from it. When we think of 

 beauty of colouring in birds, it is their plumage which 

 at once presents itself to the mind, and yet a gizzard 

 has a real beauty both of shape and hue. This organ, 



