184 NATURAL THEOLOGY, 



chemistiy.^^ For the preparatory grinding the giz- 

 zard lends its mill ; and as all mill-work should be 

 strong, its structure is so beyond that of any other 

 muscle belonging to the animal. The internal coat 

 also, or lining of the gizzard, is, fo?^the same pur- 

 pose, hard and cartilaginous. But, forasmuch as 

 this is not the sort of animal substance suited for 

 the reception of glands, or for secretion, the gastric 

 juice, in this family, is not supplied, as in membran- 

 ous stomachs, by the stomach itself, but by the gul- 

 let, in which the feeding -glands are placed, and 

 from which it trickles down into the stomach. 



In sheep, the gastric fluid has no effect in digest- 

 ing plants, unless theij have been previously masti- 

 cated. It only produces a slight maceration, nearly 

 such as common water would produce, in a degree 

 of heat somewhat exceeding the medium tempera- 

 ture of the atmosphere. But, provided that the 

 plant has been reduced to pieces by chewing, the 

 gastric juice then proceeds with it, first, by soften- 

 ing its substance ; next, by destroying its natural 

 consistency ; and, lastly, by dissolving it so com- 

 pletely as not even to spare the toughest and most 

 stringy parts, such as the nerves of the leaves. 



So far our accurate and indefatigable Abbe. Dr. 

 Stevens, of Edinburgh, in L777, found, by experi- 

 ments tried with perforated balls, that the gastric 



** One of the many modes by which seeds are carried to a dis- 

 tance, and Sir Joseph Banks gave us reason to bcheve that it serv- 

 ed as a preparation for sowing, as seeds so carried germinated 

 ooner. 



