348 DISEASES OE THE INTESTINES. 



lamellae of an onion. The earthy matter has been found by 

 Fourcroy and Vauquelin to be an ammoniacal magnesian 

 phosphate. Girardin examined one, which he found to 

 consist of : — 



Ammoniaco-phosphate of Magnesia . . . .48' 



Phosphate of Lime 19* 



Water of Composition 14" 



Animal Matter '80 



Soluble Salts, &c 6*60 



Extractive Matters 4* 



Fatty Matter 7* 



Loss '60 



100- 



The second kind, soft, loose, friable, and without dis- 

 tinguishable lamellae in its structure, appears to be a compo- 

 sition of earthy and mucous and stercoraceous matters min- 

 gled together. 



The third kind consists of dry hardened dung' and masses 

 of imperfectly changed hay and corn, and, perhaps, straw as 

 well, agglutinated together by the mucus of the bowels. 

 There is a fourth kind — a ball composed of hair ; but I am 

 not so sure about this being found in the horse : in cows, 

 who lick themselves, the production is common enough. 



Why Calculi should form in a horse^s bowels has no 

 right to surprise us, when we know that, on occasions, not 

 only is much dust swallowed with his food, but that the 

 voracious feeder is disposed, whenever he has the opportu- 

 nity, to lick up and swallow a great deal of dirt. Horses 

 picquetted while troops are encamped, will commonly first 

 tear up and consume every blade of grass or weed within 

 their reach, and afterwards will eat the roots, even the very 

 earth in which they grow ; a propensity not, perhaps, natural 

 to them, but one engendered from being dissatisfied with 

 their scanty rations, as well as from having nothing else to 

 divert attention when their food is consumed. Even in the 

 stable, dusty hay is often given ; and oats full of grit and 

 fragments of stone. Millers' horses are said to be especially 



