RUMINATING ANIMALS. 91 



This is of a cellular structure in its interior, and in- 

 dependent of its general use to retain water alone, 

 it appears that longer deprivation from liquid enables 

 the animal to dilate the cells, and renders the com- 

 partment capable of containing a greater quantity of 

 its invaluable store. 



The horns, the hoofs, and hair, present peculia- 

 rities in the ruminating animals. The horns in 

 many of the species, particularly in the deer of 

 temperate climates, are deciduous annually ; and 

 when the nourishing vessels, as it were, become ob- 

 literated by their growth, they lose their vitality, and 

 fall off, to give way for the reproduction of the new 

 material, which commences about the period when the 

 system becomes influenced by the desires of rutting. 

 In these animals, it springs from, and is for the time 

 attached to, the prolongation of the frontal bone, 

 which serves as a base or root ; and when in its per- 

 fect state, or when the complete obliteration of the 

 nourishing arteries takes place, it is of the consist- 

 ence of bone, and remarkably compact and hard, en- 

 tirely different in composition from the substance of 

 true horn, as seen among the Bovidse or Oxen, &c. 

 Sir Everard Home looks upon their consistence as 

 similar to bone, and thus describes their formation : 

 " Besides the common bones of an animal body, 

 there are others peculiar to particular animals, which 

 only last for a season. Of this kind are the bony 

 projections or horns on the skull of the deer, pecu- 

 liar to the male. As these are of quick growth, and 



